Settlement of a construction in permafrost regions results from several simultaneous processes, each with a different mechanism. The first is thaw settlement due to the degradation of the permafrost underneath. The second is creep, including creep of warm frozen layers and creep of unfrozen soil in the active layer in warm seasons. Third, because freeze-thaw cycling in the active layer can change soil properties; extra settlement would also take place in the first years. These three processes are interactive, which makes any single attempt of calculation very difficult. Based on field investigations and practice of construction and maintenance of Qinghai-Tibet railway and highway, these three processes were analyzed previously.

There are a lot of people inhabitancy caves locating in loess zone. The loess mass surrounding cave can be supported by loess arching formed in the process of excavation, which can maintain the stability of caves. The shape of arch in loess cave excavation was determined by the limit sliding line method and verified by the site measurement information. The bearing force of arch and stability parameter of wall rock was calculated by the limit sliding line method. It is shown that two kinds of earth pressure method determined loads on lining structure can be the same with the different suitable conditions

A widely accepted two-parameter theory proposed by Fredlund for unsaturated soils uses the net stress and suction as stress-state variables; it cannot consider the effect of saturation degree or water content on the stress-strain behaviour and strength of unsaturated soils directly. The triaxial test results show that even if the path of net stress and the suction are the same, the stress-strain relation and strength are different due to different saturation degrees. While other conditions are the same, the higher the saturation degree of the specimen, the higher the stress ratio versus strain relation. The latest elastoplastic constitutive model coupling hydraulic and mechanical behaviours could quantitatively reproduce the above behaviours of unsaturated soils.

A series of dynamic triaxial tests were conducted on saturated remolded loess specimens under various loading conditions. A method of using hysteretic loops for each loading step to construct the backbone curve is developed. This method can utilize most of the testing information and reduce the randomicity of the tests compared with the traditional method of using only one hysteretic loop for each loading step. Hardin-Drnevich model, modified Hardin-Drnevich model and Martin-Darvidenkov model were then used to simulate the test results. Using this method, the accuracy and parameter sensibility of the above three backbone curve models were discussed respectively. Results show that Hardin-Drnevich Model can’t always simulate test data accurately in different test conditions. Modified Hardin-Drnevich Model and Martin-Darvidenkov model are more effective to simulate test data and they can reflect the softening characteristics of the backbone curve. Considering that Martin-Darvidenkov model is more sensitive than modified Hardin-Drnevich model, modified Hardin-Drnevich model is suggested to be used in the dynamic simulation of loess under complex loads.

In shearing strength theory for unsaturated soil, the suction friction angle is a key parameter, it is difficult to determine its value, which is limited by the test of equipment, technology and method. The influence factors for such as the soils′ basic physico-mechanical properties and the test method are analyzed detailedly. At the same time, by using qualitative analysis and quantitative calculation methods, it is considered that those factors have a certain degree of nonlinear relationship, which includes dry density, water content and internal friction angle. Based on artifical intelligence——the BP neural network, the 4:9:1 network structure is built to calculate and predict the suction internal friction angle for unsaturated soils. The validity of the model shows that the precisions of simulation and prediction are high. This model can be applied to forecast the index of the suction internal friction angle .

The strength characteristics of unsaturated red clay is an important calculated parameter of foundation engineering,slope engineering and underground engineering. The strength characteristics of Guiyang unsaturated red clay are studied by the triaxial test.The stress-strain relation and breakage type for original red clay and compacted red clay are discussed.The mathematical model of stress-strain relation for compacted red clay is presented. The relation between shearing intensity parameters and physical properties is obtained.

Based on Mononobe-Okabe’s postulation, the first-order differential equation for passive earth pressure on the retaining wall was set up for the translation(T)mode, movement modes of rotation around base(RB)and rotation around top (RT) by analyzing slice elements extracted from sliding soil wedge; and the formulas for calculating of the unit earth pressure, the resultant earth pressure and the action point of resultant pressure were given. The comparison between calculated results by the present formulas and Coulomb’s theory shows that the unit earth pressure is nonlinearly distributed; and that the distance from the action point of resultant pressure to the base of wall increases with the order of (RB)mode, (T)mode, and (RT) mode.

CTMAB is a new organic cationic surfactant. A chemical improved experiment is based on CTMAB towards to the natural expansive soil; and the improved mechanism and effect are studied. The result shows that the plasticity and expansibility of stabilized expansive soil decrease significantly compared with plain soil; and its water stability increases obviously. Soil samples remain enough strength after repeated dessolution different times, which indicates that CTMAB can effectly improve the engineering properties of expansive soil. The achievement patent has been authorized.

To investigate the stability of loess slope in Yangling district of Shaanxi province, a series of laboratory undrained triaxial creep tests of loess specimens taken from a slope are performed by stress triaxial creepmeter. The test results indicate that the creep characteristics of loess are obviously influenced by water content, dry density and consolidation pressure. When the water content is invariable, the creep strain reduces with the increase of consolidation; when consolidation pressure is invariable, creep phenomenon is significant with higher water content and the creep strain becomes bigger; as dry density increases, the creep deformation of soil specimen becomes smaller. In the treatment of loess slope, enhancing the drainage ability of loess slope and increasing the compactness of soil can reduce the probability of creep rupture. According to the analysis of experimental data, a new empirical creep model is proposed; it shows a significant advantage of better applicability, higher accuracy and fewer parameters in simulating the creep characteristics of loess in Yangling district after the comparison with Singh-Mitchell and Mesri models.

Aeolian sandy soil sampled from Hobq Desert was reinforced by PX soil stabilizer. A experimental studied was carried out on the strength characteristics of solidified aeolian sandy soil in different water containing states, different percentages of soil stabilizer, and different maintenance ages. Experimental results indicate that, the strength characteristics of aeolian sandy soil are different in different water containing states. The unconfined compressive strength of solidified aeolian sandy soil in optimum water content is much than the strength in saturated water content for the same stabilizer percentage and same maintenance age. The unconfined compressive strength of solidified aeolian sandy soil increases with the increase of stabilizer percentage and maintenance age in the same water containing state; and it increases quickly at the beginning of maintenance. While the stabilizer percentage is 8 %, the maintenance age is 28 d, the strength could meet requirement of international solidified sand. The shear strength of solidified aeolian sandy soil advanced obviously than aeolian, while the stabilizer percentage is 8 %, both the cohesive force and the internal friction angle reached max, and the shear strength of solidified aeolian sandy soil is 1.8 times as much as the aeolian. Furthermore, the change of the microstructure of the solidified aeolian sandy soil is studied by scanning electron microscope. Experimental results indicate that, the connection between grains changed from weak connection to adhesive bonded connection after mixed with PX stabilizer, explained the internal reasons why the solidified aeolian sandy soil’s strength could increase and its stability could advance.

Soft soils in ravines is a weak soil layer widely distributed in the valleys and gullies, the deformation of which has a direct impact on the settlement of the roadbed. On the basis of sampling at the scene and by using a variety of laboratory test means, we did some indoor rheological experiments to some sections’ soft soils of Heng-Yan highway, and then found several rheological constitutive models that are in keeping with the rheological characteristic of ravine soft soils by analyzing the rheological curve.At the end, we obtainde the model parameters by method of undeterminated coefficients. The deformation characters of three types of soft soils in ravins have been gained by tests. This paper will give some references for the handling of ravine soft soils in filling roadbed and the evaluation to the roadbed settlement after construction.

Burnt rock is a special kind of rock which is formated from rock whose property has been changed due to coal autoignition. Its physico-mechanical property had been tested in laboratory. The results show that its moisture content has a little reduction; however, its mechanical strength is improved generally; and its Poisson’s ratio has a little reduction too. The splitting conditions of crack tip are analyzed under grouting pressure. Based on this, the code of grouting spreading extent in fractured network is made by employing Bingham grouts spreading model, which can simulate the grouting spreading in intermitent fractured network. Finally, the grouting test is done in burnt rock mass in Ningtiaota Coal Mine; and the grouting pressure is optimized by utilizing grouting spreading program. Comparing the actual spreading extent to the simulating result, they are comparatively anastomotic. The program can guide the grouting parameter design and construction.

Using a red volcanic ash taken from Jingyu County of Jilin Province as a raw material, samples with five different grain gradations are prepared. The specific density is measured by specific density test and the shear strength and compressibility of volcanic ashes are tested by direct shear test and one-dimensional consolidation test. The influence of grain gradation on shear strength and compressibility of volcanic ashes is also analyzed for the application of volcanic ashes in engineering practice in the future. It is found that the shear characteristics of the red volcanic ash samples are similar to dry sand; and the samples all belong to medium compressible soil.

Fly ash is a byproduct dumped out of thermal power plants which use coal as one kind of fuel. It is urgent to consider how the vast quantity of harmful fly ash resources can be utilized. There are a large number of potential solutions to this problem; an effective disposal method is to use it as a fill material for dam construction or filled ground. Fly ash is a uncompacted lightweight material with a lot of pores. On one hand, it has a superior engineering capability in many aspects; On the other hand, pure fly ash lacks any necessary cohesion so that it has a very sensitive reaction with water which is an undesirable effect on the safe operation of the project which employs pure fly ash. Based on above considered, the engineering performance of the fly ash can potentially be enhanced by mixing different quantities of clay into fly ash, therefore the study of mechanical properties of fly ash mixed with different quantities of clay could help to promote the engineering application of fly ash. The fly ash taking from the Xianyang Weihe Thermal Power Plant as the object of study, and different quantities of loess are used to obtain the mixed-soil fly ash, then the engineering characteristics of fly ash with different quantities of soil mixed are studied via compaction test, compression test, and direct shear test as well as triaxial compression test. Furthermore, the trends of influence of different quantities of soil mixed on deformation and strength characteristics of fly ash are also obtained. The research results will offer the basis for both the effective utilization of fly ash and the improvement of its engineering property.

China lacks construction experiences with common methods in inclined mine shaft of thick gravel layer. Combined with construction practices of the first inclined mines of Cailiao and Huifeng in Yili coal mine, the supporting programme is designed and quite a few supporting trials have been studied due to abundant water and non-aqueous sites. According to the field test results, the deformation of trestle gets larger and it is more difficulty to support in the abundant water site; The temporary support of beam joined with reinforced concrete is an effective method to support the large section inclined shaft in non-aqueous gravel layer. The deformation and the pressure grow rapidly while the shaft is in the abundant water gravel; it is proved that forepoling supporting together with the temporary support and reinforced concrete can control the surrounding’s deformation and keep its stability. It is inferred by site test results that significant errors might occur when it is applied to calculating the pressure of gravel layer surrounding by Terzaghi and Coulomb earth pressure theory.

Based on the existing results attained by the variational limit equilibrium method, two assumptions of the horizontal slice method are analyzed. Results show that the distribution of active earth pressure intensity along wall height is very sensitive to the action point position coefficient of the normal force acted on the top and the bottom of the soil slice; the action point position coefficient of the normal force is the function of the wall height and is 1/2 only in the special case; the horizontal slice method enlarges the earth pressure intensity at wall top and decreases the earth pressure intensity at wall bottom; thus the position of action point is moved up.

By using the fracture model based on the principle of energy balance, nonlinear fracture toughness tests on undisturbed frozen soils were conducted. According to the variational rules of heave quantities, the frozen depths and time at different depths, the temperatures were controlled strictly when the specimens were being made and tested. The nonlinear fracture toughness and of modelⅠ straight crack specimens are obtained, which make a meaningful attempt and spread the thoughts for the research of nonlinear fracture toughness of undisturbed frozen soils.

In the deep disposal of highly radioactive waste, the engineering barrier made by densely compacted bentonite is used to prevent the groundwater infiltrating and the radioactive waste diffusing; and the gap between the bedrock and nuclear waste canister can be filled up by the hydro swelling bentonite. The permeability and swelling behavior of bentonite are needed to be carefully studied. It is Gaomiaozi (GMZ) bentonie from China to be investigated here. A series of laboratory tests were conducted including test for determining water retention curve, permeability coefficient test in swelling condition and mercury; intrusion porosimetry (MIP) test after that. A mathematical model is established for the relationship among permeability, swelling volumetric strain, void ratio and suction of GMZ bentonite. Equations of the model indicate that the permeability coefficient and swelling volumetric strain increase with suction decrease. The reason is that the decrease of suction can cause the increase of void ratio of bentonite which will cause the increase of permeability coefficient. This discovery can facilitate the design of deep disposal of highly radioactive waste.

The reinforcing effect with PS shows that the initial water content and density of loess have influences on test result through the direct shear test and seepage test. It can be easily found through the test with various water contents and different densities samples. The results show that the strength can be enhanced evidently with the 9 % water content sample, when all the samples have the same density. But the seepage tests have a different results that the permeability varies nonlinearly with the water content. It is found that the PS has the best reinforced effect when the water content varying between 8.5 % and 11 %.

The assumption of existence of total plastic zone is made in the upper bound limit analysis, i.e. there exists a sliding body satisfying yielding equation in slopes. However, the mobilized extent of inter-slice strength is taken as optimized variables in this paper; and multiple solutions can be obtained by using virtual work-energy equation. The solution which is the biggest among those multiple ones is used to assess the stability for given sliding body. Two soil slopes are analyzed using the proposed method; and the results are compared to those by general upper bound method. The effect of this assumption on the stability results is given.

Taking the case of frozen soil in Fuxin city of Liaoning province,the frozen-heave factor of ten kinds of frozen soil have been experimentally studied under the condition of analogizing groundwater level. The test results indicate: there is a obvious effects of anti-freezing for the frozen soil in Fuxin city of Liaoning province when replacement layer is above the groundwater level about 30 cm,the largest deep-freeze for 62 % and the thickness of the deep freeze 30 %.

Calculating foundation deformation by using chord modulus is a China's self-innovation technology. It corrected the faults in compression modulus and various calculation models.,and improved the calculated result. The calculation is based on physical indicators of soil and by software; therefore it is also a simplest method. According to it the goal that to control the deformation in the foundation design specification can be reached. Also, taking region differences and micro-structure differences of soil into consideration, the software can calculate the collapse of different types of loesses considering the factors such as the footing area, foundation pressure, adjacent footing influence and so on, thus assessing the quantitative loess collapsibility. During almost the same time when the chord modulus is being researched; it is also researched in the calculation of metal material deformation in USA, which has replaced method of calculating nonlinear elastic deformation by using the Young’s modulus and was then introduced in China's related specifications.These facts should give us an important inspiration for technology update to use chord modulus in code for design of building foundation. The paper is going to summarize the chord modulus and further clarify this views.

In order to search for suitable structures of relief well for Dongting Lake region, the decompression effects of geotextile tied holey plastic tube, steel tube, sand filtration and no-sand concrete were analyzed through laboratory tests; and then suitable filter structures of relief well have been tested for Dongting Lake region Hejiadi Relief Well Project. The results indicate that the plastic blind drain and capillary plate relief well are suitable for the seepage control of Dongting Lake region.

The effective stress ( –ua) and the matric suction (ua?–uw) are regarded as variable of state to describe the stress state of unsaturated soil; so its Mohr-Coulomb shear failure plane is a curved face (usually assumpted as plane face) in three-dimensional system of coordinate that is made up by effective stress, matric suction and shear stress. The damage variable of unsaturated soil is defined based on equivalent strain principle. In light of triaxial test, the relationship between damage variable and deviatoric stress is fitted; and the relationship between damage threshold stress and matric suction is shown as the exponential function. As an example, method of stabilization numerical analysis for a slope of unsaturated soil is given.

In order to study the effect of traffic loading induced static deviator stress on the deformation of saturated soft clay, an undrained dynamic triaxial test is designed. The traffic loading is simplified as sine wave plus static deviator stress. And the rule of plastic deformation development is analyzed based on the examination data. The semilog plot of turning strain against failure vibration is presented and the influence of static deviator stress on it is studied. It is found that the bigger the static deviator stress is, the faster the deformation develops and the fewer cycles are needed to achieve the turning strain. The slopes curves of turning strain against failure vibration decrease and the intercepts are close when the static deviator stress incereases.

It is difficult to study instability mechanism of coal seam because the traditional methods are mostly questioned. In view of present situation, the strain magnitude in horizontal direction due to tectonic action has been calculated based on in-situ stress measurement in hard rocks combined with spring model. Taking the strain magnitude in horizontal direction as boundary condition for in-situ stress finite element analysis, a finite element model is set up to invert in-situ stress field of coal seam. Combining the in-situ stress measurement in hard rocks, theoretical model and finite element numerical simulation, a new method for research on in-situ stress in coal-bearing seam has been developed. The borehole stability of coal seam of well LP-1 in Jingbian gas field has been studied with the method, and the results show that the borehole stability is good when drilling along the direction of minimal horizontal in–situ stress, and it is bad when drilling along the direction of maximum horizontal in–situ stress; and the borehole stability when drilling along the bisecting lines ranged from the maximum to the minimal horizontal in–situ stresses falls in above two cases.

Based on SMP criterion, a new strength criterion is proposed for anisotropic geomaterials. Through the transformation between the principal stress space and the physical space, a normal vector of the SMP is transformed to the physical space. Assuming that the friction angle is changed with the angle between deposition and the SMP, a new expression of anisotropic strength peak Mα is proposed, which can represent the anisotropy associated with particles’ orientation distribution. Verification by experiment data shows that the anisotropic strength criterion can be used to describe the anisotropy of soil strength variation.

A part of air in soil is easily surrounded by water flow and entrapped in the pores of unsaturated soil in the infiltration progress. The entrapped air is neither continuous with each other nor with the external atmosphere. Thus the water flow is encumbered and the permeability is decreased, which results in great influence on infiltration. Based on the previous research and the results of one-dimensional ponded water infiltration in the laboratory, a preliminary research on the formation of entrapped air and its influence mechanism on infiltration are conducted. This research is important to understand the water-air two phases flow in unsaturated soil. The test results show that the entrapped air is found in all ponded water infiltration tests, which is related to soil type, dry density, and initial water content. The entrapped air occupies more void in larger dry density sample and has greater influence on water flow. Under the same dry density condition, the entrapped air in clay soil affects infiltration greater than that in sand soil. The less the initial water content is, the greater the entrapped air volume is. At the steady state of infiltration, the water content is about 80 % to the saturated water content.

Formation pressure distribution of non-Darcy flow in low permeability reservoir differs from Darcy flow in custom reservoir, and there are non-startup regions uncontrolled by single well. Based on mass conservation and momentum equations in theory of fluid mechanics in porous medium, the non-Darcy flow mathematic model considering threshold pressure gradient is established, which derives analytic solution of non-Darcy radial flow and deliverability equation. A new calculation method of formation pressure is presented, which provides theoretical foundation for reservoir evaluation and development design of low or ultra-low permeability reservoir. The calculation results demonstrate that there is not exciter response everywhere of non-Darcy flowing in low permeability reservoir which differs from Darcy flowing in custom reservoir. Energy decay rate of non-Darcy flowing in low permeability reservoir is faster than Darcy flowing in custom reservoir. Because of small spreading range, it exists reasonable employing radius.

In petro-industry, mining, hydroelectric engineering, express way, rail way, and nuclear waste disposal, nonpenetrative fractured rock mass is one of the most important and common materials. The full understanding of fractured rock mass property is the first and the most important thing in order to know it, to use it, and to improve it. In most cases, failure mode of fractured rock mass is dominated to its property, so it is important to study and research it. Based on the failure mode and the structure of the fractured rock mass, which are critical for understanding its property and characteristics deeply are studied. According to the structure of fractured rock mass, the research results are achieved by the former scholars or drawn from literatures, studying methods, analytical perspective; the merit and the disadvantage of physical and numerical model tests and site experiments are discussed, the key issues in researching work are pointed out, and the solution plan is made out.

There is more important effect of dilatancy of soils on the slope stability; however, the dilatancy is not considered in the traditional limit equilibrium method. The relationship between friction angle and dilatant angle determined by the material state-dependent critical state constitutive model, then the slope stability is analyzed by the limit equilibrium method with the equivalent friction angle considering the dilatancy of soils. The case studies show that it is very important to analyze the influence of dilatancy on the slope stability in the limit equilibrium method.

One of the slope treatment measures is the replaced-backfilling clay treatment in the Luwangfen test region of middle-route of South-to-North water division project. The engineering property of replaced-backfilling clay is studied by physical test, compaction test, expansive property test and in-situ test. Studies show that: (1)the diversity of particle component of it is obvious, in which sand grain and silt are dominant, gravel is lesser, cosmid and colloidal particle are least；(2)the optimal water content of replaced-backfilling clay is 17.7 % with the corresponding maximum density of 1.71 g/cm3 under the condition of light compaction, the optimal water content is 18.4 % with the corresponding maximum density of 1.87 g/cm3 under the condition of heavy compaction；(3)the specific gravity of replaced-backfilling clay is 2.7, liquid limit is between 37.6 %－38.7 %, plastic limit is between 17.1 %－19.2 %, plasticity index is between19.4－21.2, therefore, it belongs to low liquid limit clay；(4)when the sample of replaced-backfilling clay is selected within the depth of 3.5 m, the free expansive rate is within 40.0 %, which means there is no expansive potential; when the sample is selected between the depth of 3.5－4.5 m, the free expansive rate is between 42.0 %－76.0 %, which means there is middle or weak expansive potential; (5)there is no obvious relation between ( ) of replaced-backfilling clay and depth, but the module parameters of it has the decreasing tendency with the increase of water content. The result provide scientific reference for the application of replaced-backfilling clay to the middle-route of South-to-North water division project.

Some improvements are made based on the Hilf method. The pore air pressure and pore water pressure can be calculated regarding the pore air pressure and pore water pressure as independent variables. The analysis method of stability on the strengthen of embankment with clotty is given when the pore air pressure and pore water pressure are all taken into account. The results show that the stability coefficient increases with the enhance of matric suction; and once the pore air pressure is ignored, the stability coefficient a little bigger than it is in fact. The pore air pressure has no influence on the resistance of shearing. when is equal to ; and the calculated stability coefficient is the same. Not only the pore air pressure and pore water pressure must be taken into account; but also the adding of clotty of ground is considered when the stability of embankment is analyzed during the construction period.

In order to study the critical dynamic stress of lime-treated expansive soil under cyclic loading, the dynamic triaxial tests under different water contents and different vibration frequencies are carried out. Based on the test results, the analysis of brittle failure mechanism of lime-treated expansive soil under cyclic loading and the discussion on the affecting factors of the critical dynamic stress are carried out; it is shown that the plasticity of expansive soil decreases after lime treatment, and its brittle property appears; the quality control index (dosage of lime and compactness) is the decisive factor for the critical dynamic stress. And the influence of water content on critical dynamic stress of lime-treated expansive soil appears limited because of its preferable dynamic water stability. However, the influence of the type and the extent of external dynamic and static loads (vibration frequency and confining pressure) is so little. Namely, on condition of stable dosage of lime and compactness, the critical dynamic stress of lime-treated expansive soil is usually stable over a small range.

Surface average air temperature was obtained in frost-thaw period based on the relationship between air temperature and ground temperature in the permafrost regions. Active-layer thickness of permafrost at any time and any space point can be determined by the relationship between air temperature and ground temperature. Furthermore, variation laws of permafrost thickness with time are obtained and the relation formula for air temperature, mean ground temperature, active-layer thickness and base plate thickness change of permafrost correlated with time are established. Soil-pile interaction is analyzed considering air temperature, and models of soil-pile interaction are bulit. Synthesizing relation formula, models of soil-pile interaction and vertical bearing capacity of single pile formula in Code for Design of Soil and Foundation of Building in Frozen Soil Region, a prediction model in which some factors of air temperature, ground temperature, active-layer thickness, permafrost thickness change correlated to the bearing capacity of pile foundation has been established, so as to provide scientific basis for predicting working conditions of pile foundation varying with the air temperature within designed life cycle.

The identification and classification of swelling rock are important for its research. A new criterion is proposed that in which the montmorillonite content is a basic control index; the dry saturated water-absorptivity, limit swelling quantity, limit swelling power are main indices. And it has been used for analyzing an actual engineering.

Soils structure is the essential intrinsic factor that it decides mechanics characteristics of soils. It is an effective method that the researches of soils structure characteristic are based upon the theory of comprehensive structure potential. This method not only can consider the characteristics of the soil particle arrangement (i.e. the geometric feature of soil structure) and the soil particle linkage (i.e. the mechanic feature of soil structure), but also can general, holistic, dynamic quantify soils structure characteristic. The soils structure parameters have been summarized and reviewed comprehensively in this paper, consequently the naming of structure parameters has been unified. The current situation of the relations between strength or deformation and structure parameters, constitutive models of structure parameters, application of structure parameters have been generalized. In the mean time the rational approaches and the influence for structure property and consolidated state to strength and deformation of soils have been analyzed. A new method that the strength and deformation should been studied in the condition of same structure parameters is proposed.

Based on the basic principle of shear strength reduction, three calculation models of earth pressure for the clay are derived by considering the displacement effect, the calculation results are all agreed well with the centrifugal model test results. No matter from the theoretical perspective or from the calculated values aspects; the second method is the most reasonable among the three calculation models, but it has an applicable scope. The scope is the displacement must be in , that can also be generalized to . Beyond the scope the model one and the model three can all be used.

On the basis of coulomb’s concept that the earth pressure against the back of a retaining wall is due to the thrust exerted by a sliding wedge of soil between the back of the wall and a plane which passes through the bottom edge of the wall and has an inclination of θ, the basic analysis equation are set up by considering the equilibrium of the forces on an thin-layer element of the wedge. By using the equilibrium equation of the moments on the whole wedge, The lateral coefficient of earth pressure , the earth pressure distribution along the wall back, the resultant force of earth pressure and the application point of the resultant force are obtained. Finally, a case study is given to verify the proposed method. The results show that the calculation values are very consistent with the measured values. It is indicated that this calculating method is feasible and reliable.

The water swelling whole process of different weathering degrees swelling red sandstone with whole weathered, strong weathered, intermediary weathered and weak weathered was revealed in micro and fine by scanning electron microscope and digital image technique and amplifying the particle composition structure diagram before and after weathering 300 times. The water swelling whole process includes: water absorption→hydration→volume increased→producing expansive force→expansive force over limit→disintegration. It was viewed from this course that the hydrophilic of part mineral in swelling rock was the reason of swelling deformation characteristics. Encountering water, the hydration reaction of hydrophilic mineral led to volume enlarging and expansion stress. When the expansion stress was more than cement cohesive force, the disintegration would generate. The weathering degree was higher, and the process of water swelling was more quickly, and the time of reaching disintegration was shorter.

Effects of two specimen-preparing methods on tensile strength of remolded loess are studied. The first method adopts standard layered-bumping to make sample whose layer interfaces are vertical to tensile force (sample 1). The second method uses compaction apparatus to prepare big sample and the big sample is cut to prepare triaxial sample whose layer interface is parallel to tensile force (sample 2). Test results indicate that the sample 2 has higher tensile strength; and layer surfaces in sample 1 decrease its tensile strength.

Usually, shear failure is a central form of geomaterial failure. The point safety factor which considers this form of strength safety allows us to inspect the safety condition of every part in the structure. It is also an essential reference for analyzing structure safety, especially for structures controlled by key points. The definition of the point safety factor applicable to different shear failure criteria was concluded by the way of extending the point safety factor definition of Mohr-Coulomb shear failure criteria into the three-dimensional generalized Mohr space; and it is known that the Mohr-Coulomb shear failure criterion is widely applied to geomaterials engineering. Furthermore, we have also obtained the solving method of the minimum point safety factor of shear failure geomaterials, the relationship between the minimum point safety factor’s corresponding deviatoric stress and shear stress on the most dangerous section and even the failure conditions for an integral safety degree. By applying this definition and approach, the structure safety conditions of different shear failure geomaterials could be inspected and estimated. Thereby, the quality of engineering construction could be improved.

A series of consolidated undrained static triaxial tests and cyclic triaxial tests were carried out on undisturbed marine silty clay of Bohai Bay; the cyclic triaxial tests consist of cyclic load and post-cyclic undrained shear 2 stages. It was shown that with the increase of cyclic stress ratio, the average axial strain and single amplitude axial strain become large; when cyclic stress ratio large than 0.4, average axial strain and single amplitude axial strain increase fast with number of cycles; average axial strain increase with confining stress, while single amplitude axial strain decrease with confining stress. Under large cyclic stress ratio, normalized average pore pressure and normalized single amplitude pore pressure come to a stabilization with number of cycles; with large cyclic stress ratio normalized average pore pressure and normalized single amplitude pore pressure become large; with large confining stress normalized average pore pressure become small, while the effect of confining stress on normalized single amplitude pore pressure was unapparent. In post-cyclic undrained shear stage, the effective stress path in q-p’ plane and pore pressure exhibit the properties of over consolidation clay.

Through adjusting the working parameters of temperature and humidity in the constant temperature and humidity equipments and changing the expansive soil evaporation path, the non-uniform shrinkage test of saturated expansive soil under different drying rates is achieved, which combined with swelling test and direct shear test to research the expansion and contraction characteristics and strength properties of expansive soil under non-uniform shrinkage test. The experimental results indicate that the smaller the drying rates is, the larger the deformation of the expansive soil and the higher of the shear strength is. The contraction, shrinkage deformation and shear strength of the expansive soil under uniform shrinkage condition are larger than non-uniform shrinkage condition. The main reason for these differences is the different paths of evaporation in non-uniform shrinkage test, which leads to different water contents along the depth direction, different matrix suction and different strain. The non-uniform shrinkage changes the homogeneity of expansive soil and limits the expansion and contraction characteristics and strength properties of expansive soil.

In order to eliminate the accumulative probability errors resulting from the use of the indirect variables in the Hoek?Brown empirical formulas, it is presented that the reliability analysis of rock mass stability should be implemented directly starting with the basic variables of the empirical formulas. On the basis of a brief introduction of the mechanical parameter estimates with the Hoek?Brown formulas, the safety factor of a micro-unit was first defined according to its stress state; and a performance function containing the basic variables of the empirical formula was established. The Rosenbleuth point estimate method was chosen to calculate the mean and standard deviation of the safety factor of element. With the combination of the point estimate and finite element methods, the calculation of the stability reliability of the rock mass was described. The stability analysis of a cut slope shows that the results calculated by the reliability analysis method, are consistent with the occurred failures of the slope. The recommended method is convenient to estimate the stability reliability of slopes, foundations and underground caverns related to the rock mass.

In order to eliminate the calculation inaccuracy, considering the effect of the angle of internal friction on the inclination of the sliding plane of soils behind retaining wall, considering the deflected principal stress as soil arching effect, the horizontally earth pressure factor is calculated for different friction angles of soil and friction angle between wall-surface and soil based on the analysis about minor principal stress of soil arching elements to study the vertical stress. The theoretical formulae of the active earth pressures, the resultant earth pressures and the points of application of resultant earth pressures were obtained based on the method which satisfies the equilibrium condition. The formula presented is compared with some experimental observations. The results agree well with those of the experimental observations.

The testing results of dynamic shear modulus and damping ratio of silty clay in Chongqing downtown area are attained with the change of shear strain by natural (resonance) column test and dynamic triaxial test. Besides, the differences between test value and recommended value from Reference [1] and code value from Reference [2] are compared and analyzed. Furthermore, the influence of such difference on surface response spectrum is initially given through soil response calculation; and main conclusions are drawn as follows: (1) In Relation G/Gmax-γ, G/Gmax given by code value is lower than that of test value and recommended value during moderate strain; code value attenuates faster than test value and recommended value during large strain. (2) After Gmax normalization, relation G-γ bears more consistency than relation λ-γ; and damping discreteness of silty clay is relatively large. (3) The difference of surface response spectrum calculated by test value and recommended value is relatively small; while the difference calculated by test value and code value is relatively large. And such difference is more obvious with the increase of input ground motion strength. Analyses show that in the process of soil dynamic calculation in Chongqing downtown area without testing data of soil dynamic characteristics, the application of code value has certain limitation and risk; and to some degree recommended value bears more applicability than code value.

Thermo-hydro-mechanical behaviour is highly nonlinear and complex. It has extremely important application value in concerning these three coupling functions researches in many domains, such as the petroleum engineering, the geothermal resources development, the underground nuclear waste storage security, the mining engineering, and so on. Because of the differences of the research object ,the forms of the THM coupling models exist differences; it is difficult to build modes of THM that accord with actual problem. This article is based on the reaches of the scholars’ models of THM, and the modelling process with ADINA are described in detail.

The process of the chemical subsurface erosion dissolve settlement of the saline soil is divided into three states and two stages; of and the interrelation of the physical parameters of saline soils is summarized. Through analyzing this relationship, the key stage which the dissolve settlement happened is known. The quantitative relations about the coefficients of the saline soil’s dissolve settlement and the soil’s physical parameter are derived. The result is that the void ratio, the salt quality, the form of the soil structure are important factors effecting the dissolve settlement of saline soils.

Using the SLB - 1 triaxial and permeability apparatus with stress and strain control, triaxial tests with stress and strain control have been carried out on the intact loess of Shaanxi Yangling; the tests were carried out under consolidated undrained condition with different stress paths, which include conventional triaxial compression, reduced triaxial compression and with constant p. The influence of different stress paths on structural parameter of loess is studied. The experimental results indicate that, under different stress paths, with the increase of confining pressure, the structural parameters of the loess isn’t always increasing. There is a peach when the confining pressure is 300 kPa; while the moisture content of loess is relatively higher, the structural parameter of loess is relatively smaller.

Based on the classification scheme of expansive soils which can be used as embankment fillings, an experimental research on physical properties, compaction behaviors and strength characteristics for three different expansive soils to verify expansive soils in Baise-Longlin expressway of Guangxi Province can also be directly used as embankment fillings .Combining with the effect of entity engineering, the used CBR strength, the swelling rate of CBR sample in the modified CBR test and the consistency, which are used as classification scheme for embankment filling of expansive soils are verified to be reasonable. According to the comparison between the standard CBR test and the modified CBR test, the modified CBR test evaluating the CBR bearing strength of expansive soils is further verified to be reasonable. According to the unsoaking CBR test of Baise expansive soils, it shows covering and packing method in treating the expansive soil embankment in Baise-Longlin expressway is feasible. The entity engineering by using No.1 expansive soils whose behavior is the poorest as embankment fill and red clay as surrounding soil is satisfactory . From indoor and outdoor tests results, the three Baise expansive soils can be directly used as embankment fill are drawn.

Based on different initial water contents and dry weight densities, the peak intensity and the residual strength of Baise compacted remolded expansive soils under different vertical pressures are studied; and its action mechanism of shear strength is analyzed shear. The research indicates: along with the increase of dry weight density, the peak strength of soil increases, the residual strength changes little; along with the increase of overburden loading, the shear strength of soil increases obviously, which shows that using physical treatment technology filling expansive soil subgrade can ensure its strength and stability. The residual strength of remolded expansive soil is not related to its structure, stress history, and initial water content, it is only decided by clay particle shape, size, content and mineral components.

Based on a hyperbolic model of soil, water content instead of matrix suction is introduced into the hardening parameter of the model to develop a constitutive model on unsaturated soil as simple and feasible as possible. A theory which the disturbed soil sample renews primary stress state before test is put forward, and the test method is improved by it. In order to study stress-strain relation for different water contents, the test simulates undisturbed soil with remolded soil. The test result shows that stress-strain relation of remolded unsaturated cohesive soil essentially accords with hyperbolic model which Kondner put forward. On the basis of studying rule for parameters a and b in the hyperbolic model, functions between parameters a and b and the water contents under confining pressures of 100, 150, 200 and 250 kPa are established. And then the stress-strain relation which the water content is 24.52 % is predicted. The contrast between testing data and predicted results shows that predicted error is relative small, and the results satisfy the demand of expectation.

Seepage field, temperature field, deformation field are coupled,namely fluid-solid-heat coupling, which is highly complex. Fluid-solid-heat coupling issue involves many areas, its research is receiving increasing attention. The importance of research for the porous medium fluid-solid-heat coupling is expounded; and the research progress of porous media fluid-solid-heat coupling, is discussed and summarized; finally, the direction of further study is forward.

Aiming at the problems of being apt to teeth collapsing, cracking, corroding fallen layers and excessive wear and tear in drilling complex and hard formation of PDC bit, PDC drilling/milling characteristic test equipment independently self-developed was used and drilling/milling characteristics of five kinds of φ19 PDC sheet, five kinds of φ16 PDC sheet and seven kinds of φ13 PDC sheet were tested and evaluated. The results show that the PDC sheets from different manufacturers and different sizes have different drilling and cutting characteristics including latter diamond exposure and direct diamond exposure. Drilling speed is from low to high and then to low for the kind of latter diamond exposure, but from high to low for the king of direct diamond exposure. Therefore, to improve the quality of PDC bits effectively, the specification and size of PDC sheet should be chosen reasonably in manufacturing process of PDC bits.

At present, the primary measure Is clearing foundation in patchy permafrost regions, which slove the permafrost issues under the highway subgrade in Heilongjiang province. The influences induced by clearing foundation or not are analyzed by the method of field investigations and numerical simulation calculation. The study indicates that the project of clearing foundation or not is feasible. But it is disadvantage to the heat stability of subgrade by clearing foundation. The significant influence takes place in the 1－3 years after the highway constructed; during which artificial permafrost table increased obviously, but not resulted in a large area of subgrade thawing settlement. The long-term influence by clearing foundation made the annual average ground temperature increase and artificial permafrost table in middle of subgrade reduce in permafrost regions. It also developed thawing core in soil profile ahead of almost four month in subgrade; and the thickness of thawing core in soil profile would increase about 0.3 to 0.6m than without clearing foundation. Through above analysis, the main influence factors that caused greater effect on thermal field of roadbed by clearing foundation are the season constructed and initial temperature of soil after backfilling.

A numerical simulation is carried out to study the settlement of ground caused by the construction of a shield tunnel. As a high speed railway is just above the tunnel and the differential settlement of the steel rails is limited in 5 mm; it requires high quality of the tunnel construction. The simulation results indicate that the grouting reinforcement to the stratum between the railway and the tunnel is an effective way to control the settlement of ground; and the values of several parameters gained in the calculation can serve for reference in the construction.

In order to have a profound understand of the internal force and deformation rules in loose areas of the loess tunnel caused by the construction process of tunnel, some axial force meter of bolts, single-point displacement transducer and embedded earth pressure cells were embedded into the loose areas during the Tian-Ding freeway tunnel construction, which lie in the Dingxi city of Gansu Province, China. Based on the measured data, combining with the on-the-spot construction state, the internal force and surrounding rock displacement change rules at loosed loess area are analyzed and summarized. According to these rules, the later construction of the tunnel have carried some corresponding adjust and achieved satisfactory result. The results also have an important guidance for the design and construction of similar loess tunnel.

Xi’an Metro Line No.2 is an a important track traffic network south-north main stem of Xi’an city. For its construction, the key problem is crossing the earth crevasse. In light of the problem mentioned above, the structural design measures and waterproof project of metro section crossing earth crevasse, are described in detail. For the activity of earth crevasse, The structural measure is: "Prevention" and "release" the combination, The structure adapts The deformation of the earth crevasse primarily; The structure cross section expands, reservation distortion space, The structure cross section expansion reservation distortion space, the structure partition addition distortion seam adaptation distorts, the attachment to use the flexible connection, Strengthen the structural strength to resist deformation due to structural damage;Simultaneously adopts Frame plank structure being adjusted, assures the operation security; Waterproofing measures taken in the special way, using a large-strain properties of the new unique Design project of waterproof.

Zhengzhou-Xi’an passenger dedicated railway line is 350 kilometers per hour ballastless track; its allowable subgrade settlement should be less than 15 mm after completion of the subgrade. In order to meet the requirements, the relevant tests are carried out; and the collapsible loess subgrade treatment principles are determined. And the subgrade are treated successfully by using cement-soil compacted piles, long and short piles and embedding continuous pile-board structure. The achievement will be reference to the upcoming construction of Xi’an-Baoji passenger dedicated line, Baoji-Lanzhou passenger dedicated line, Xi’an-Chengdu passenger dedicated line.

Taking the Dingxi tunnel as the background, deformation rules of its typical cross-section’s surrounding loess are studied by using the finite-element software; meanwhile, by field monitoring; then the results of numerical simulation are compared with field measurement in order to get the state of stress which brought to the optimal parameters of initial support after excavation. Based on the above, some advices and techniques for initial support in the similar region, are put forward.

The engineering mechanical properties of saturated, water-bearing sandy ground, instability failure mechanism and stability control of tunnel surrounding rock are key issues in water-bearing sandy ground tunnel design and construction. Based on the review of research on sand strain localization, the water–bearing sandy ground tunnel surrounding rock stability research is described emphatically. Some issues in progressive failure of water-bearing sandy ground tunnel surrounding rock are presented, which need to be further studied. These works will be helpful to improve the level of bearing–water sandy ground tunnel design and construction.

The effects of the cut-off wall depth on the cofferdam seepage characteristics and its slope stability under earthquake, are studied by using numerical analyis. And the seepage characteristics of the wall and its dynamic stability are compared with a certain depth of the cut-off wall-the closed type and any other depth of it. It is shown that the closed cut-off wall can significantly reduce hydraulic gradient; and hence, make benefit to slope stability.

The inter-pile soil can be fully mobilize to participate in the work of load-sharing and vertical rigidity change in the trend be the same with the additional load stress dispersion changes under the action of long and short piles high strength composite foundation. Based on the calculation model of long and short piles composite foundation considering different lengths of piles, different stiffness of piles and soil layer distribution around the pile, long and short piles high strength composite foundation of high-rise building can be calculated and analyzed; through a case study, it is shown that the long and short piles high strength composite foundation can meet the requirements of the bearing capacity and settlemen of high-rise buildings. The high-rise construction pile foundation will face enormous challenges, because of its high bearing capacity, economic superiority, flexible construction and short construction period.

The load-settlement relationship, the composition and ratios of pile head settlement of overlength large diameter piles are analyzed with FEM in different situations of geometric parameters. The following rules are obtained according to the calculated results: the big settlements are needed to bring the ultimate bearing capacities of overlength large diameter piles into play; and the required settlements increase with increase of length-diameter ratios (L/D). The deformation of over-length large diameter piles are mainly controlled by the compression deformation of pile shafts; the proportion of pile tip settlement is low; and there is a function relation between the proportion of each composition of settlement and length-diameter ratio. For the over-length large diameter piles with L/D=50-83, the proportions of compression deformation of pile shafts are 65.2 %-71.83 % in the ultimate states; and the proportions of settlements caused by the pile end loads are 15.7 %-9.72 %; under the working load states, the proportions of compression deformation of pile shafts are 66.1 %-72.5 %; and the proportions of settlements caused by the pile end loads are 10.8 %-3.9 %.

A 3-D finite element analysis by applying Duncan model is carried out to calculate stresses and deformations of the Gangqu River concrete faced rockfill dam. The effects of 3-D soft rock fillings on the behavior of the dam are discussed. The displacements and stresses of concrete slab and rock fillings as well as deformations of peripheral joints are calculated. The maximum settlement of the cross-section is found to be located at the downstream side with a value corresponding to 0.2 % of the dam height. The displacement of peripheral slab joints is small, less than 2.0 cm during reservoir impounding. The type of watertight and joint sealing material should be selected carefully. The effect of the 3-D characteristics of canyon shape on the behavior of CFRD is found to be significant. Numerical simulation results provide for reference in design and construction.

Load on pile top is acted after the settlement of soil surrounding the pile in bearing capacity test of piles in collapsible loess, and it is acted before the settlement of soil on general working condition of pile foundation. Different mechanisms of pile-soil interaction between such two loading sequences are simply analysed. Finite element method is used to calculate the differences. Analysis results show that settlement of pile increases, neutral point goes down and dragload induced by negative skin friction reduces as the load on pile top increases in both loading sequences. It also shows that comparing with load on pile top acted before in general working condition, loading sequence of bearing capacity test in collapsible loess would make the neutral point position in pile lower, settlement of pile smaller and the dragload in pile smaller. The differences of neutral point position, settlement and dragload in the two loading sequences increase gradually as working load increases. At every stage in both loading sequences, there exists small differences on distribution and development of skin friction along the piles. This will cause the testing result of bearing capacity of piles relatively unsafe in collapsible loess zone

Using GeoFBA, a load-structure method tensile-compressional model is established for analyzing and calculating the tunnel which is 30 m depth embedment in surrounding rock Ⅳ, and is eroded by combined effect of chloride and freezing and thawing cycles. The load-structure model is installed tensile spring in the range of 152° of the arch crown; and the left part is set by compressional spring. The calculation indicates that first of all, the tunnel safety falls down gradually with the increase of circumferential crack width (the corrosion degree of reinforcement) as well as longitudinal crack depth; furthermore, when lining suffers the same corrosion degree of reinforcement and the same depth of longitudinal crack, the problem occurs on the arch crown which would bring up bigger effect on the tunnel safety than that occurs in the haunch; in addition, the change of circumferential crack width, which is smaller than 0.2 mm, would make less influence on the tunnel lining safety

Soil-rock mixture landslide is a representational geological disaster of landslide. This landslide is broadly distributed in nature, and it is more complex than other landslides, it often brings huge calamity to human. Zhoujiawan landslide which is located on the north bank of Yangtze River, Country Badong, Hubei Province, China, belongs to this type of landslide, It is a very important part of the Huanglashi ancient landslide group. The obvious deformation of the landslide began in the middle age of 1980s, and at that time the deformation of the landslide induced many cracks on the ground. Now the deformation of the landslide is pricking up, and it is on the creep stage. The existence of Zhoujiawan landslide is a potential threat because there is a Shiliushubao landslide at the front of Zhoujiawan landslide. The special factors like geological surrounding, shape, structure and evolvement of the landslide are analyzed by means of geological analysis and engineering geomechanics. The three-dimesional geological model is also established. The stability of the landslide and the failure mechanism are studied through the numerical simulation technique

The influences of elastic module of pile on negative skin friction (NSF) is simply analysed. Elastic compression deformation of pile is a key component of displacement at pile top in low elastic module piles. The influences of elastic compression of pile on load-transferring are evident in such cases. For low elastic module piles which are often used in composite foundation, have to take compression deformation of piles into account in analysis of pile-soil interaction. Finite element analysis shows that elastic module of pile that affects NSF exists a critical value. Influences of elastic module of pile on NSF can be neglected when elastic module of pile is greater than the critical value. Compression deformation of pile body increases while elastic module of pile is lower than the critical value. It makes the neutral point in pile move up and the maximum additional stress in pile play down. These changes become more evident as lowering elastic module of pile

The compaction method used to control the subsoil of collapsible loess can eliminate collapsibility and improve bearing capacity of loess effectively. For serious collapsible loess in a power plant to be constructed, pre-bored compaction lime-soil piles (down-hole dynamic compaction method) field test studies were carried out. After the construction of the test piles were finished, a lot of in-situ tests including plate loading test, standard penetration test, etc., were used to evaluate the bearing capacity of the soil between piles, the piles and the composite foundation, and to test the deformation parameters. Especially, comparative research between natural status and soaked status of composite foundation as well as comprehensive evaluation of effects of ground treatment were carried out

The faults produced by the deformation and motion of Earth’s crust are distributed on the geotechnical foundation engineering. The fault foundation includes the upper rock mass, lower rock mass and the structure surface. It is necessary that the properties of rock mass, structural surface, deposit history, and structure function are considered in design of building. The principles of design and construction are excavation from ground, non-disturbing, increasing strength, anti-seepage and draining freely. The fault is reinforced by some effective measures including filling, arching, lining, settling well, supporting with column and pile, anchor and so on.

In permafrost region, the key about the stability of earth structure is itself thermal stability. If retaining wall would be built in permafrost region, it would change the heat balance of ground layer and the upper limit of frozen soil or depth of seasonal-thawing would change. The stability of engineering structure would be affected by the heat balance change. So it is value to study the development of the upper limit of frozen soil or temperature field distribution according to the seasonal change. In this paper, considering the only retaining constructing - L type retaining wall in section from Golmud to Lhasa, Qinghai-Tibet railway, we test the temperature along the cross-section of retaining wall. We analyze the upper limit of frozen soil or depth of seasonal-thawing of typical backfill. The distribution shape of depth of seasonal-thawing in different cross-sections has been obtained; and the temperature field distribution according to the seasonal change has been regressed also. From testing we know that the ground heat balance has been destroyed by excavation and construction. As an open area engineering structure, the ground heat balance could be recovered gradually if there is no new disturbance. In addition, the effect of freezing force or frozen-heave force shouldn’t be neglected. In a word, the design idea and the engineering measure have been studied in this paper. All these work want to be benefit for future engineering application

An example of composite ground of low energy level dynamic compaction combined with CFG pile, which is used in Guizhou mountainous area, is presented to elaborate technology and job practices of the proposed method. In addition, the results of static load test, dynamic penetration test, low strian reflection wave method and settlement observation which will provide creative ideas and experiences for recent fillingsoil work in mountainous area are summarized.

Through adopting the method of filling grouting to dispose the earth quake fissure at the engineering of Dongerhe Reservoir and Dahebian Reservoir, a solid consecutive valid slurry of compounded cement-clay in the fissure is formed; and then the compactness of dam body and the ability of resisting deformation of dam dody are improved, thus achieving desired filling results for coming into being the fissure subsequent in time to earthquake

According to a project in Xi’an, vertical static bearing tests and axial force tests of two bored piles with post-grouting technology have been carried out. And then axial force transfer law , working trait of side resistance and tip resistance of post-grouting piles in loess foundation are analyzed. Finally the effect of post-grouting technology on bearing capacity of bored piles is discussed.

Landslides cause substantial damage to property, which is seriously hampering social development. With the use of geographic information systems (Arcview), a risk assessment system is established. A 3D geo-information model is drawn into the system. The failure probability of 3D-slope is calculated by using Monte-Carlo method. The risks of life and economic losses are also calculated based on vulnerability analyses. By a case study, the results of the risks of life and economic losses may be crucial foundations for administrant branch based on the 3D geo-information model.

Geo-mechanical parameters have structural and stochastic properties on spatial variability, which causes the uncertainty of geo-mechanical parameters. The Kriging method and variant function are used for analyzing the spatial variability of geo-mechanical parameters of rock and soil. Theoretical model of variant function is employed as the mathematical model for depicting the spatial variability law of geo-mechanical parameters. Demonstrated by example, the Kriging method for parameter estimation is revealed the filtration effect and agglomeration effect. The different weight coefficients can effectively provide the variability estimation of geo-mechanical parameters.

High-speed railway bridge settlement conformity is a major measure to ensure the high-speed railway construction quality. Through accumulating the observed data of settlements of a large number of high-speed railway bridges, and then analyzing the process of settlements of soft soil by using curve fitting the settlement deformation laws which is practical application value, the development of settlement law can be predicted. In order to predict the whole process of bridge base settlements and make carve fitting, through a variety of theoretical calculations and a large amount of the settlement analysis of observed data statistical induction, the following index of the deformation process method is proposed first. The results have been applied to the Beijing-Shanghai High-speed Railway and other related projects to predict their foundations’ settlements

With the widespread use of shield tunneling technique, many accidents appear, and it is necessary to introduce fault diagnosis technique in shield tunneling to avoid similar accidents appear again. In essence, the fault diagnosis technique in shield tunneling is the problem of pattern recognition, which can be realized by means of the BP feed forward neural network. Combined with the production examples in Guangzhou region, the practical application of BP feed forward neural network to realize the fault diagnosis is analyzed and discussed. Computation example shows that it is feasible to use BP feed forward neural network to realize the fault diagnosis. Of course, the accumulation of the data of typical faults should be strengthened and increase the degree of separation among faults in order to the increase the effectiveness of the fault diagnosis.

Structure displacement of the running metro station caused by adjacent foundation construction should be controlled strictly so as to keep the normal operation of the existing metro station and guarantee the security of the existing station structure. Based on the running metro station adjacent to foundation excavation in Shanghai, by superposition principle and load-structure method of FEM and forced displacement method, the stability and permissible deformation of the standard station structure are analyzed and back-calculated according to the mode of fracture control and strength control separately. The result can be used to the standard for deformation control of station structure on foundation pit construction

In light of the built loess tunnels, the engineering geology and hydrogeological conditions have been investigated and analysed. Some support measures and construction methods have been summarized. Meanwhile the engineering problems for loess tunnels have been pointed out. It is shown that the collapse is the main project problem. The main cause making engineering problems is the gather water corridor around tunnels. The main positions of destruction is import and export segments and the stratum in which the geological conditions would be changed suddenly.

As the basic method to obtain rock and soil’s physical-mechanical parameters, the soil test plays an important role in engineering design, construction and quality inspection. According to the experiences of doing experimental work over the years, the author offered their thoughts on a number of related issues. ①Taking the soil sample of a power plant in Tangshan for example, the mechanical properties of a special sand with certain clay in it ,which is widely distributed in Hebei and Inner Mongolia are discussed. ②Combining with the test requirements in technical standards, some viewpoints on "the pressure of consolidation" and "continuous loading with strain control " in consolidation test, are put forward. ③For the characteristics of unsaturated soil with less water content in the northern region, the reasons why the soil shear strength test is difficult and the results are not exact, are analyzed. Finally, some advices in favor of practical applications in projects are proposed

The slope displacement is an explicit process of the complicated dynamic system involving many mutual facts. And the physical modeling is very difficult to fulfill prediction function. As an alternative, it is proved by many study work in which a set of displacement time series to predict the future displacement can be used; and united many different methods as a new predicting model was a principal trend of study. Based on this, a novel model based on wavelet transform and genetic¬ algorithm -least square support vector machine (GALSSVM) for slope nonlinear displacement forcasting is proposed. Firstly, slope displacement time series are decomposed into different frequency signals through the wavelet transform. Secondly, phase space of each signals is reconstructed, and time delay and embedding dimension are determined by mutual information method and false nearest neighbor method respectively.Then, the respective forcasting model of genetic¬-least square support vector machine is constructed according to different characteristics of each phase space. Lastly, the predicted results of the signals are reconstructed to be used as the final prediction result of slope displacement. As a test, this model has been used in displacement prediction of DANBA slope. The results indicate that it is reliable with high precision; and it can be used to practical engineering

The Fen-Wei basin is the most serious area of the ground fissure formation in China. Xi'an is located in Fenwei basin and the exposed surface of the cracks and fractures were found concealed in 15. Based on the existing knowledge, the new point about the causation of Xi'an crack is raised. According to the research of Xi'an crack on the current status of activities and its development trends, the cracks in the surface with the largest width and length of metro security is raised on the expert advice and the latest research. The MTR measures to deal with cracks are raised on the analysis of the impact and failure mode on the structure which is caused by the cracks. Based on the existing knowledge and research, analysis of the development tendency of Xi'an cracks and the MTR measures to deal with cracks will contribute to the development of urban underground track

Effective combination of GIS and 3D visualization technology can have complementary advantages of them to be used for engineering geology information management. Integral and macroscopic management based on GIS and 3D modeling for partial skimming and spatial analysis of assisted management are specifically discussed. This method can be well used for actual engineering management.

The problem of deposits slope is often encountered in constructions of hydropower projects in Southwest China. The study combines geology phenomena and drill core data, based on areal geology survey, rainfall data, and so on. The thought of engineering geology qualitative analysis is applied to study on the slope stability. On the basis of geological analysis, the deposits body has the feature of multi-stages and composite formation mechanism, and it is one of typical evolution models of the bank slope of Nujiang Great Canyon. The coupling effect mechanism of endogenic and exogenic geological processes of the deposits body is proposed. Aiming at spatial structure features and special location of deposits slope, the finite-difference and strength-reduction method is adopted to compute its stability factors under natural, rainstorm, seismic conditions. The above discussions offer reasonable evidence to constructions of the project and partial reinforcements of the slope and provide reference for stability analysis of similar deposits slopes in the river basins.

Based on analyzing the site geological-conditions of a natural gas storage station, a high slope formed by excavating is treated by using spray anchor and framed anchor. Two methods, a limit-equilibrium way from Chongqing local norms and other numerical simulations, are used to analyze and evaluate the treated slope reliability comprehensively. The results show that the slope stability factor, after the implementation of project management, may comply with the requirements of safety norms, and the designed bolts have no damage. The effective treatment of the slope can meet the safety requirements of the natural gas storage station.

The study work of surface subsidence has been mostly focused on shield construction of underground tunnel, while there has hardly been any research on surface subsidence caused by mining method constructing city double-arch tunnel. Based on the double-arch tunnel in Pengjia Garden, the study of surface subsidence caused by mining method construction has been carried on. Under the conditions of different construction methods, the regression analysis pointed to different depths of embedment, different section areas is used, so that the law of surface subsidence is obtained in theory; according to the monitored data, a forecast formula of surface subsidence under mining method is put forward. The regression effect has been validated combining with three dimensional numerical simulation

Auxiliary tunnels of Jinping Ⅱ hydropower station are deeply buried. Rock burst under high geo-stress is one of the main problems to be taken into account. With the statistical data of the rock burst in the auxiliary tunnels and the in-situ stress and the mechanical properties of the rock, risk of rock burst in the auxiliary tunnels is analyzed by using different indexes. In addition, the prevention and cure methods of rock burst in the auxiliary tunnels are discussed. The results can provide basic support for rock burst estimation and prevention in the process of construction of four diversion tunnels in Jinping Ⅱ hydropower station.

The exist problems in rocky desertification control and ecological restoration research on mountains areas in Bijie region are analyzed specifically. As for the specific characteristics, such as ecological restoration of mountains rocky desertification in trial areas poverty alleviation, and ecological construction, ecological restoration must be carried out combining with man-made restoration and self-healing restoration. Some necessary attentions are proposed to rocky desertification control in mountain areas and ecological restoration; and the development direction is put forward in mountain rocky desertification control.

Liquefaction of saturated sand is a major problem in engineering. The large-diameter gravel piles with vibroflotation are used to control the liquefaction of large-thickness saturated sand of a proposed power plant project, and many field test studies are carried out. After finishing the construction of the test piles, a lot of in-situ tests including plate loading test, ultra-heavy dynamic penetration test, etc., are used to evaluate the bearing capacity of soil between piles, piles and composite foundation, to test the deformation parameters, and to evaluate the controlling effects of liquefaction. A large number of reliable experimental data are obtained, which are valuable for similar projects

After proposing the concept of “cohesive soil containing calcareous nodules”, the distribution law, genesis, age and types of calcareous nodules of cohesive soil containing calcareous nodules in Huaibei Plain of Anhui Province are studied in detail. Based on field geology studies, tests, exploration and extensive reference to engineering geological exploration reports and professional literature data, the burial and distribution law of cohesive soil containing calcareous nodules are analyzed; and the plane distribution map and typical strata section maps of cohesive soil containing calcareous nodules are drawn. Cohesive soil containing calcareous nodules mainly distributes in the block between rivers, depression and the Yellow River Flood Plain in Huaibei Plain. The change law of the elevation of the roof of cohesive soil containing calcareous nodules and the ground elevation is basically identical. Calcareous concretions can generally be divided into three forms: embryonic calcareous concretions, mature calcareous concretions and calcareous hard pan. It is pointed out that there are embryonic calcareous, mature calcareous and calcareous hard pan from up to down on profile, the particle size and number of calcareous concretions increase gradually with depth and calcareous hard pan comes to being around the perennial groundwater level. In addition, the radiocarbon ages of embryonic calcareous, mature calcareous and calcareous hard pan gradually increase on profil

The earth-rock dam with clay core of Shenyugou dangerous reservoir in Fang County is studied, whose seepage and dam slope stability are evaluated, aiming to provide strength design with reference. Three kinds of stable seepage computing conditions such as check flood water table, designed flood water level and normal storing stage are designed and computed. Two types of unstable seepage schemes, from check flood water table to normal storing stage and lowering from normal storing water table to dead water level, are done. Moreover, five kinds of lowering velocities are designed by the latter unstable seepage scheme. Slope stability of dam is calculated at each seepage step. It is found that stability of downstream dam slope doesn’t meet to the engineering requirement under three stable seepages’ and two unstable seepages’ conditions. So the reservoir is a dangerous one, and is in need of strengthening

Ground surface settlement is an important factor to evaluate surrounding rock stability of shallow tunnel. Based on analyzing of the relation between surface settlement monitoring importance and the depth tunnel, determination principles of the settlement standard are discussed. Focusing on the section without neighboring structures, settlement standard of the ground surface is studied considering rock stability, empirical formula and relative codes. The method is applied to Liuyang River tunnel in Wuhan-Guangzhou passenger dedicated line. Results show: urban tunnel’s deformation standard is lower than mountain tunnel’s standard; shallow tunnel’ deformation standard is lower than that deep tunnel’s; the harder the rock is, the lower the deformation standard is; the smaller the tunnel span is, the lower the deformation standard is; the higher the side wall is, the lower the deformation standard is; the main influence factor is the rock’s property, the next is tunnel span

The research advance and existent insufficiency of unloading relaxation in rocky slope excavation are summarized. Based on the qualitative analysis of unloading relaxation process and mechanism, the limit tensile strain of rock is proposed as the criterion of unloading relaxation. The value taking principle of limit tensile strain of rock is put forward by analyzing the relationship between lab test value of limit tensile strain of rock and its tensile strength, and by referring to the successful practice of excavation unloading relaxation analysis in Xiaowan arch dam. The calculation method of tensile strain in rocky slope after excavation is deduced. By adopting three-dimensional elasto-viscoplastic finite element method of reinforced jointed rock masses, this unloading relaxation criterion and corresponding calculation methods are applied to the numerical analysis of rocky slope excavation unloading relaxation in Jinping First-Cascade arch dam foundation plane. By comparing to the disclosed situation after actual excavation and the sonic wave testing data, the results of numerical analysis are confirmed reasonable, so as to provide beneficial guidance to the construction of project.

A high energy dynamic compaction for collapsible loess is discussed in detail; some problems should be paid attention to Some advice about design, construction and detection for foundation treatment of collapsible loess is given. It can be a reference for collapsible loess, and insure the quality of foundation treatment.

Luohangtan landslide is one of the important landslides in Gushan hydropower station of Hanjiang, it is an accumulational landslide of collapsing soil, the volume is about 70 × 104 m3, it is a medium-sized landslide. According to a field survey, preliminary analysis shows landslides are stable for current state overall. For status quo，heavy rain and reservoir impoundment, the landslide stability is calculated, the results show that：in status quo conditions, the landslide is stable; under heavy rain and reservoir impoundment conditions, landslides on both sides are in poor stability, the landslide stability of middle part is better, however, the instability of landslides on both sides is bad for the stability of middle part. Landslide failure is more harmful to the project; using lardslide treatment combining with filling materials for cofferdam as removal measure is proposed

A slope of a power plant is located in the II and IV-class terraces of Yellow River; its maximum height is 55 m. The slope is composed of Pleistocene loess, silt, sand and gravel layer and lower Pleistocene pebble gravel layers. The basic earthquake intensity of the site is 8-magnitude. The loess has collapsibility. The construction of the power plant and the operation of cooling towers and other buildings will make the moisture content of the soil have a certain increase. Contrapose the features of the slope, mechanical parameters of soil under multi-rate of water content are obtained through investigation, multi-working conditions are chosen for the slope design. Only based on the understanding of the slope characteristics and deformation and failure mode, selecting suitable parameters of reasonable working conditions, can the slope design meet the engineering practice, and achieve safe reasonable, economical and applicable

We have some construction about 3000－15000kN m energy dynamic compaction for collapsible loess. Through comprehensively analying the results of standard penetration test, soil mechanics experiment, cone penetration test, Rayleigh test, static test, and comparing with other energy dynamic compaction result of collapsible loess, some outcomes of effective reinforced depth and coefficient of collapsibility are obtained. Finally, an empirical equation for dynamic compaction of this area is proposed; and it can be for reference in design, construction and detection of collapsible loess

Sections of double layer compound liner test of second-line terminal tunnel for Baoji–Lanzhou railwag are modeled and analyzed by using ANSYS software, safety factors of the surrounding rock are calculated by strength reduction finite element method, and safety factors of the liner are calculated by applying finite element method based on the combined effect of soil and structure. The loess tunnel design must meet the two stable requirements: according to the preliminary proposals, the safety factors of the surrounding rock can’t be less than 1.15 to 1.2; at the same time, the safety factors of the initial liner can’t be less than 1.3 after the initial support; the safety factors of the liner are greater than 2.0 to 2.4 after the second liner so that the construction and operation security can be ensured. Evaluating and analyzing the safety factors of the surrounding rock and the liner, quantitative methods of designing loess tunnel support structure are formatted.

As human engineering activities become more frequent and the scales expand more and more broadly, a large number of catastrophic accidents induced by the instability and destruction of the anti-dipped slopes in the world, that accidents occur in a variety of engineering projects such as hydraulic projects and hydropower stations, mines, railways and urban environments. But such comprehensive engineering geological problems were gradually being recognized and studied in the early 1960s. A comprehensive review of the worldwide research on the deformation mechanism and stability analysis methods of the anti-dipped rock slopes is put forward. Finally, the existing problems and further study direction are discussed.

A numerical simulating method of forecasting the building settlements and its distribution characteristics using engineering analogy is introduced. A regional standard stratum system is established firstly; and then the project stratum is normalized according to the stratum standard established. The parameters for numerical simulation are obtained by inversion analysis. At last the settlements of new building can be predicted. The effectiveness of mothed is proved by comparing the simulation results with actual observation values in two projects

The dynamic compaction tests with 8 000 kN m, 6 000 kN m, 4 000 kN m and 3 000 kN m energy-levels for treating desert soil in Inner Mongolia were carried out. And then through the standard penetration test, cone penetration test and the static plate loading test on the desert soil after dynamic compaction, for different levels of dynamic compaction of the desert area of fill areas, excavation zone after reinforcing, the respective effective treatment depths and bearing capacities of reinforcement are obtained. Some rules of dynamic compaction treatment on the desert soil are summarized; some construction parameters of dynamic energy level, effective reinforcement depth, spacing, etc. are given, so as to offer for reference in the similar geological conditions for the foundation treatment works with dynamic compaction.

The article puts forward that the observation time and single observation result have large effects on the final settlement which is predicted by conventional forecasting methods based on analyzing Zhengzhou-Xi’an passenger dedicated line test section subgrade settlement. As a result, predictive value may not real value. The article puts forward that the development of subgrade settlement is an easing up process. It can be significantly divided into consolidation deformation stage and rheological deformation stage based on the bases of analyzing subgrade settlement deformation curve. The viewpoint can be explained by equivalent consolidation theory. The article puts forward the method for predicting final settlement according to s- curve characteristics. The practice shows that the observation time and single observation result have very small effects on the final predict settlement. It is better than any other methods.

Reinforcement effects of prestressed anchorage piles applied to landslide are analyzed and discussed by numerical simulation model test method. The results show that: The force and load-deformation characteristics of landslide treated by prestressed anchorage pile can be investigated intuitively and quantitatively, and the safety factor can be calculated with this method. The vertical and plane deformations of landslide are decreased obviously, the landslide force is diverted to anti-landslide pile, and the safety factor was improved observably. This method is available to evaluate the reinforcement effect and interaction mechanism of pre-stressed anchorage piles applied to landslide

For the urban land-use planning and urban development, we should pay attention to the disaster prevention of land suitability evaluation. As a result of geological disasters in the existence of human life and property caused serious harm, so from the perspective of disaster prevention the urban land-use suitability evaluation should be made. Development of urban land-use suitability evaluation methods based on GIS for disaster prevention,using IDRISI software, through comparative analysis with the GIS-OWA and Boolean of decision-making and weight linear combination (WLC) and so on multi-criteria evaluation method in the distinction between strategic decision-making, the land-use suitability under the influence of geological disasters in Tangshan City has been calculated.

In accordance with the instance of shallow-buried tunnel in a highway project, it was analyzed that numerical simulation on excavation construction of the entrance of the shallow-buried tunnel under the uneven rock pressure. Firstly, the computational models in FEM were built in differently excavating cases which were often adopted in practice. Then the stability and the different distribution of deformation and stresses of the rock and liner of tunnel were discussed in the two excavating case. In the end, according to the analysis and results the preference of effective measures of excavation is suggested. In sum, the improvement scheme and research redound to the effective control of the stability of shallow-buried tunnel under the uneven pressure from stratum during construction.

A novel contact model incorporating rolling resistance proposed by Jiang et al.（2005）is implemented into PFC2D. The behavior of sand with rolling resistance is simulated by PFC2D with the novel contact model. Based on the biaxial compression test, the effect of rolling resistance on the behavior of sand is studied. And some microscopic parameters including the average coordination number and force chains are studied too. The results show that the rolling resistant is very important in controlling the peak strength and leading to extensive dilatancy of sand. With rolling resistance the loose sand can also have a strain-softening and shear-dilantant behavior. With the increasing of the rolling resistance, the average coordination number reduces

In order to research that the effect of meso-concrete material heterogeneity on the static properties of concrete cylinder sample, different random numbers are employed; aggregate size is fixed and size of the concrete samples is changed; different three-dimensional numerical models of concrete are established; the same uniform load is divided into six steps to impose on the models; the effect of various ratios between aggregate and sample radii on mechanical properties of concrete is simulated. The results show that: with the ratio increasing, the error square sum of strain is reduced. The effect of aggregate random location on the concrete samples is decreased; and the brittleness of the samples becomes obvious.

The characteristics of clastic grain flow along a non-uniform slope have been discussed based on the controlling equation presented by Savage. The effects of bed friction coefficients, internal friction angles of clastic flow, initial velocity and the slope angle are mainly analyzed. It is shown that the movement of clustic flow is obviously different under different combinations of factors. The internal friction angle and the slope angle affect the movement configuration and the maximum movement distance obviously. However, the bed friction affects the maximum distance little because it only affects the grains near the bed.

Soil-nailing walls are main support structures in silty and clay soils. Calculated modes interacted between soils, shot crete layers and soil nail are set up on the basis of ABAQUS FEM software by employing soil constitutive model of Mohr-Coulomb and compact pattern of small slip. Distribution patterns and regularities of horizontal displacements of soils and shotcrete layers, shotcrete layer pressures and axial forces are explored. The results show the maximum value of soil displacements is at or near top of walls. Horizontal displacement of pit bottom decreases from pit base to middle pit, and trends to be a fixed value gradually. Axial forces reach maximum in the middle of the nails, and shotcrete layer pressure is much smaller than that of axial nail value. The pressures of the shotcrete layers of soil-nailing walls increase with depth, reach the maximum values, and then decrease afterward. The pressure is added to shotcrete layers with each excavation, and the position of the maximum value moves downward gradually.

The basic features of finite element software ABAQUS are introduced briefly; and the hierarchical single surface（HISS） model was developed based on the further development platform provided by the software; and two numerical examples were also solved. The correction was verified through comparing the calculation results of ABAQUS with the results computed by Desai and the test data of model test. The basic procedures and programming essentials are presented, so as to provide reference to other developers. Meanwhile, the implementation of HISS model in ABAQUS can provide an optional constitutive model for finite element analysis of foundation of building structures in soft soil.

The diffusion of harmful gas is carried out by using numerical simulation of 3-D space under condition of forced ventilation, with the CFD module of ADINA, the software of large-scale finite elements. The flow framework of forced ventilation of tunnel has been obtained. Several vortexes are distributed nearby the heading face, which has great influence on diffusion of harmful gas. The concentration of harmful gas is highest in vortexes center, combining theoretical analysis, the variation discipline of the harmful gas is obtained with the ventilation time. This paper provides the criteria for effective ventilation in heading face of tunnel

Challenged by diversity, complexity and precision in geotechnical engineering practices, back-analysis methods are required to quickly obtain feedback parameters for numerical simulations on the basis of monitoring data with fewer but more elaborate forward numerical simulations. Thanks to the specialties of support vector regression machine(ν-SVR) and improved partical swarm optimization (PSO) algorithm with variable neighborhood, a method and process for geotechnical back-analysis is set up. And to prove the correctness and validity of the proposed method, a case study of back-analysis of the left slope of Jinping-Ⅰ hydropower station is carried out. According to the monitoring data of troublesome profile II1-II1 in project site, critical deformation parameters for forward numerical simulations are fed back with the proposed method, and the results of further simulation with the feedback parameters match the monitoring data fairly well.

Recent years buried spiral steel plastic composite pipe has been applied to drainpipe construction of many big cities with the development of sewage treatment business in China. As a substitute for traditional concrete drainpipe, it has many merits such as relatively cheap price, convenient in site installation, beneficial to environment, perdurable work life. But as a new type structure, its interaction mechanism with ambient soils still needs investigation because its application period is not long enough. Finite element method is used for numerical analysis of the interaction of buried spiral steel plastic composite pipe with ambient soils. Strength and deformation characters of buried spiral steel plastic composite pipe and ambient soils are obtained theoretically. Corresponding results can be referenced by related engineering practice.

In the area with dense and intensive buildings, the construction of shield tunnel will influence the subsiding of adjacent building. In view of the structure’s different foundations, 2D FEM is adopted to study and simulate the shield tunnel construction of adjacent structure. It is indicated as follows: the level distance from tunnel axis to building axis and different foundations are the important factors that influence surface settlement induced by shield tunnel construction; surface settlement is increased by the existence of building with tunnel excavation construction. Exceeding the ranges that surface settlement induced by shield tunnel construction, effecting of structure can be neglected

With the development of cities in mountainous area, some buildings have to be situated on rock slope subgrade in order to save land. Interaction of slope subgrade and the building become a realistic research project. By using finite element method, interaction of a frame structure and raft foundation with homogeneous rock slope subgrade is computed. The computation examples are considered in 2m, 5m and 8m building distance circumstances. Rock slope subgrade is a 10 meters high vertical slope and foundation is raft. In interaction analysis, the interface of superstructure, raft foundation and slope subgrade satisfied the force balance and deformation compatibility requirements. In three building distances circumstances, strength and deformation development of the slope subgrade are researched. The internal force and deformation of raft foundation and superstructure are researched simultaneously. Some conclusions are drawn, so as to offer for reference in related engineering practice

From the perspectives of reducing displacements of dry dock walls during the process of pit excavation, and controlling the seepage of dock walls in the course of using, the application of techniques of soil nailing wall and composite soil nailing wall widely used in deep excavation, the construction of dry dock by using numerical simulation are explored emphatically. FLAC is one of methods of numerical simulation, which is widelyused in rock-soil engineering field. The FLAC is used to simulate the working condition of soil nailing wall in pit excavation of dock chamber; and the application of stiffened cement soil mixing pile(SMW) prestressed anchor plus soil nail structure to dock walls is studied. According to the simulation results, some sconclusions at the construction of dry dock walls are drawn.