Lattice frame anchor structure is an effective engineering measure in landslide control and widely used in the reservoir area of the Three Gorges Project. The design theory and method of the structure are studied systematically. On the basis of the force analysis of prestressed cable lattice beam, mechanical model of lattice frame anchor structure is proposed and the formula of deformation and inner force of the beam with finite and infinite distance conducted respectively. The engineering design demands, steps and methods are put forward according to the research. Taking Taijitou landslide in Badong County of the Three Gorges reservoir region as an example, lattice frame anchor structure is applied to the control project design; and the design process is introduced in detail.

Three-dimensional shrinkage tests are developed for use in determining index of volumetric shrinkage with respect to water content for expansive soils in Guangxi, China; and for use in heave predictions of expansive soil grounds. Static cone penetration tests are used in expansive soil investigations, and its test results (the relationship between specific penetration resistance and depth of expansive soil deposits) are used to determine active zone of expansive soils. A theoretical formula is developed to determine cracking depth of expansive soils. Depth of active zone from static cone penetration tests and from theoretical formula are identical to results from survery in situ. Idealized moisture boundary profile for Guangxi expansive soil is given to calculate ground heave. Ground heave of expansive soils is used as the basis for classification of expansive soil ground. The results of expansive ground heave have significant meaning to the choice of foundations of buildings in expansive soil grounds.

Upper bound limit analysis of slope stability is only applicable for proportional loading. In case of alternate loading and unloading, a shakedown analysis is necessary for its long term safety evaluation. Actually, besides gravity load, groundwater is also an important factor to slope stability. However, groundwater level usually changes with the rainfall or some other environmental factors, which may induce alternate wetting and drying to part of the slope. This is a disadvantage for the slope safety. In this paper, an upper bound shakedown analysis based on strong version of Koiter’s theorem is presented to analyze slope stability under such as an alternate load. Safety factor, which is defined by shear strength reduction of the materials, is adopted by a quantitative analysis to represent the influence of alternate load on slope stability. A simple example is adopted to verify the availability of this method.

How to evaluate the effects of soil structure on mechanical behavior for natural sedimentary soils is an important issue in geotechnical engineering. Burland has introduced void index in the Thirtieth Rankine Lecture for normalizing the compression curves of various reconstituted soils, and proposed the intrinsic compression line for assessing the in-situ compressive behavior of natural sedimentary soils. In this study, a series of tests were performed for natural sensitive Ariake clays deposited in Japan to investigate the engineering properties. Based on the extensive experimental data, it is found that the void index proposed by Burland has an unique relationship with a simple physical index, designated as normalized water content. The normalized water content is defined as the ratio of water content to liquid limit. The intrinsic compression line (ICL) proposed by Burland is rewritten in the simple form of the normalized water content and against the applied pressure.

Based on results of the statistical analysis of a large amount of measured data in mining engineering, the fundamental theoretical model of ground surface movements due to underground mining is established by using the theory of probability. The formulas of rock mass displacements and deformations are developed and applied to the prediction of the ground surface movements due to underground mining. The agreement of the theoretical results with the field measurements shows that our model is satisfactory and the formulae obtained are valid and thus can be effectively used for analyzing and predicting the ground surface movements due to underground mining in soft rock mining areas. The results have shown that the area of rock mass displacements and deformations in overlying strata will extend with the increase in depth.

Based on the limit equilibrium theory and traditional safety factor method, the reliability theory is introduced to analyze the stability of tailings dam. By the analysis of sensitivity and reliability of a typical tailings dam, it is found that the variation of friction angle obviously affects the reliability index and the variation of bulk density has a more obvious effect than the variation of cohesion. It is very important to use the reliability theory in the stability analysis of tailings dam. The shearing strength indexes c, and bulk density taken as essential random variables in the reliability analysis of tailings dam is suggested.

The rheological behaviour of rockfills in Gongboxia CFRD were studied with large-size triaxial test. The factors that affect the rheological behaviour of rockfills were analysed, and the affection of stress-strain acted on rockfills was studied emphatically. The law of rheological deformation was investigated. It is found that the rheological deformation reduced with time can be described with exponential curve, and it is fit for the law described as Merchant model. The rheological model is also studied, the expression of final volumetric rheological deformation and tangential creep deformation were proposed.

The gravity resistance structures on rocks (gravity dams, anchors of the suspension bridges, etc.) are born huge horizontal forces. The volume of the structure would change significantly if the coefficient of resistance changes a little for keeping resistance, which will increase the cost of the structure. The direct shearing tests have been completed with the contact surfaces between concrete and light to full weathered granite rocks. The test results show that the cohesion and the friction angles depend on the weathered degree and the roughness of the rocks. The area of the weathered degree and the roughness of the rocks are divided in the field when the pits excavated. The means of the cohesion and the friction angle are obtained by the experiment and the field test. The results are useful for check of the stability of the anchors and as reference of the similar gravity structures.

Based on the case study of external Qinhuai River dike a numerical study on the seepage stability and slide stability was carried out while considering the geomembrane placed on upstream face of the dike. The stability analysis were simulated with geomembrane under the design-flood-level and rapid-drawdown operating conditions. Especially under the latter operating condition, a simulation considering three hydraulic conductivity’s calculating schemes was carried out in the whole process of the rapid drawdown. According to these analyses, a basic safety evaluation related to the external Qinhuai River dike was made, and some helpful conclusions were illustrated between the stability of dike and geomembrane placed on upstream face. The analysis method and the results will be practical and helpful in dike engineering practice.

The basic theory and its developing process of p-version adaptive finite element are introduced in detail. The error estimate method, the adaptive upgrading strategy, the accelerating convergence technique and their applications to the field of rock and soil engineering are summarized, such as 3D elasto-viscoplastic analysis, 3D dynamic response analysis and 3D unconfined seepage analysis. Finally, the remaining problems and further studies on the p-version finite element method are proposed.

The reliability analysis of highway subgrades is carried out by using two methods of modified “JC” method and Monte Carlo simulation method (MCSM) based on the “mean rainfall amount”. A corresponding program, which can take into account relative randomly distributed variables, is developed. According to observed data, the effect of changes of saturation degree due to rainfall infiltration on soil strength parameters is discussed in detail. In addition, the sensibility factors affecting the slope stability are analyzed; and the rules of reliability of slope stability are further researched.

Landslide monitoring produces large amounts of data that can hardly be processed and analyzed manually. So an information management system is used for the management, search and analysis of monitored data. Traditionally the system is based on relation database (RDB) and can’t be easily used for the processing of spatial information. The authors developed a GIS-based management and analysis system for landslide monitoring information with Map Objects (MO), which can integrate spatial and monitoring information of a landslide to implement functions as data management, search and multiple visual analysis. The system can also run independently and can be customized in accordance with particular landslide and its monitoring program, thus making it as a general tool for landslide research. In the paper, the structure design and implementation of the system are discussed; and then its application to Xietan landslide of the Three Gorges reservoir area is described.

A series of tests on free-headed rigid piles were carried out in order to explain the instability mechanism of rigid piles under lateral loads. The soil used was unsaturated remolded silty clay. The water content of soil was between 9.85% and 13.85%. The total process load-displacement curve indicated that rigid piles would be instable when lateral loads attained to a certain amount. Visual records and soil sections showed that one shear band and one wedge were formed in the soil behind a pile with the softening failure of soil, along with one incomplete elliptic bulging and one tension crack parallel to the load direction on the soil surface. In the soil before a pile, one penetration groove was formed owing to the extrusion of the pile. The formation of the shear band is the essential reason of the instability of a rigid pile. And the extrusion failure of the soil before pile can’t play a decisive role in the instability of a rigid pile. As to rigid piles with large displacement, the essential reason of the instability is the failure of the soil mass behind piles.

Based on analyzing challenging problems in the jointed rock mass confronting the smooth blasting technology, a new blasting technology, a two-direction energy-gathering blasting technology, is introduced for the jointed rock mass. Next the basic technical principles and advantages of the technology has been dealt with in detail, so have the two design schemes. Finally, two application cases are put forward to demonstrate the application prospect of the technology.

Firstly, the paper introduces engineering geological condition and process of sliding of clayey gentle slope of Huangshan in Zhengjiang. Secondly, deformation and sliding mechanism of the landslide are analyzed. Furthermore, numerical simulation by means of finite difference method and strength reduction technique is implemented; and the result corresponds exactly to the field properties of the landslide. The clayey gentle slope stability is also analyzed considering variation of water level. The result indicates that usage of waterdrainage measure can improve notably stability of the slope.

Some problems existing in the finite element method for solving safety factor of slope stability, are analyzed. The significance of dilatancy character of rock and soil slope are considered in calculation of safety factor based on the non-associative flow criterion under plane strain condition; the traditional method which overstates or ignores the significance of the rock and soil dilatancy is modified. The results of the example show that the safety factor is increased when the angle of the dilatancy is increased; and the different yield criterions have great effect on the safety factor; the maximum error is to 30 %.

It has been noticed that polymeric solidified materials have perfect properties than the traditional ones, so they will have wide prospect. In this paper, an experimental research on the loess, which has wide distribution and special engineering properties, solidified by using the new ecomaterial of SH. The result of the mechanical behavior of loess solidified with SH is clear: the high compressive strength, the good endurance of low temperature and water. Loess-cement has been used in engineering. A comparison between loess solidified with SH and loess-cement is made. Finally, it is concluded that SH is less dosage, cheap price and good solidified effect on loess. SH is an ideal polymeric loess solidified material.

An improved method considering variable factor of safety is proposed to describe the progressive failure process of soil slopes. The proposed method includes finding the minimum general safety factor of critical slip surface and searching the optimal combination of the intension factors of the intercolumn. The double MDCP method was applied to solve the optimal problem. It is concluded that the improved method is more reasonable and more efficient than the common ones.

One-dimensional nonlinear large strain consolidation of double-layered soft soils was studied, in which the distribution of deadweight along depth due to sedimentation and the influence of varying permeability etc. were considered. The problem was solved by using semi-analytical method; and through the comparison between which available analytical solution to large strain consolidation, it is proved to be valid. Finally, the behaviour of one-dimensional large strain consolidation of double-layered soils was analyzed in detail, and compared with corresponding small strain conditions.

Although it has no similarity to any type of field compaction method，the Proctor compaction test is by far the most popular laboratory testing method, and it is widely accepted that the proctor compaction test is ineffective for cohesionless soils. Vibration compaction test for cohesionless soils needs to be improved for the practical applications. Due to the application of much heavier earth moving and vibration roller compaction equipment, soil densities compacted in the field are reaching levels that are not attainable in the laboratory. This paper introduces the test results of the gyratory test procedure conducted with Servopac gyratory compactor with 200kPa vertical pressure, 1.25 degree gyration angle, 90 gyrations, and 20 gyrations per minute，and the test results show considerable promise to be the construction specification for the quality control of field compaction for granular soils.

With the building of expressways, the problem of soft ground is becoming more and more protrusive and has been one of key factors influencing project quality, project cycle and project cost. So it has become a very important task to strengthen the research on the improvement of expressway soft ground, which affects the development of traffic project in China. In light of the randomness and uncertainty of these effective factors, a new decision model of the soft ground improvement of the highway using case-based reasoning is presented. Examples show that the model is effective, and the principle of the model is simple, visual and convenient to use.

Solution for the horizontal consolidation of vertical wall with resistance under the condition of equal vertical strain is presented.It is compared with the solution for the radial consolidation of vertical drain wells under the same condition. An equivalent calculation method to convert axisymmetric vertical drains foundation into plane strain vertical wall foundation is put forward.This method uses a simple formula when doing the conversion, and it can maintain the same average degree of consolidation of arbitrary depth at each time step, consequently it can ensure the veracity of the conversion.

The limit equilibrium methods, recommended or prescribed compulsorily in many engineering codes at home and abroad, are used to evaluate rock landslide stability. Because of the localization of limit equilibrium, there are lots of inconsequence about them. Therefore, how to improve limit equilibrium methods is one of the most important tasks in geo-technical engineering. Considering obvious weak slip zone occurring within rock landslide, the authors bring forward the different slip zone analysis methods during the calculation of finite element, and present the method combining the finite element method with non-equilibrium push transmission method used often in engineering. The method applied is used to calculate Qiancaotuo landslide stability, whose result is compared to that of non-equilibrium push transmission method based on limit equilibrium theory of rigid body. The comparison indicates that the proposed method is reliable, and can be used direct in engineering.

The ground subsidence due to underground mining can be regarded as a fuzzy event. This subsidence will take place at a fuzzy probability, and so the theory of fuzzy measures can be applied to predicting the ground subsidence and stability of building foundations. Based on results of the statistical analysis of a large amount of measured data in mining engineerings; the fundamental fuzzy model of ground subsidence is established by using the theory of fuzzy mathematics. The agreement of the theoretical results with the field measurements shows that our model is satisfactory and the formulae obtained are valid and thus can be effectively used for predicting the stability of building foundations on mined-out areas.

The triaxial test instrument for unsaturated soils controlled by stress and strain was used to measure the matric suction and volumetric water content of unsaturated soils; and a set of soil-water characteristic curves of silty clay were obtained. The equation of soil-water characteristic curve was also gained by use of nonlinear curve fitting. The concrete form of the Mualem equation was deduced based on the relation between the soil-water characteristic curve equation and the permeability function equation. The results calculated by the concrete form of the Mualem equation are consistent with those measured by the direct method. The concrete form of the Mualem equation was further proved to be reasonable.

Three dimensional geomat, as a new kind of geosynthetics for slope protection and planting, has been widely used in many fields of civil engineering. However, there are many problems in the application of geomat, particularly the choice of products lags behind the application in the engineering practice by far. The products with different strengths, thicknesses and porosities have different performance of erosion-resisting and vegetation protection. In this paper, first, based on the knowledge of hydraulics, soil mechanics, hydrology and engineering mechanics, strength design formula of geomat is deduced. Further more, by analyzing the thickness measurement and the effect of thickness on planting, satisfactory thickness of geomat is obtained. At last, through the erosion model test, appropriate porosity of geomat is found. So the problem of design indexes of geomat is solved in a way.

Combining with the research on losing mechanics of inversely oblique terrane slope, tests of similar materials of limestone are performed. The influences of sand-binder ratio, different binders proportion, and different maintain measures on sample strength are studied. The test results indicate that it is feasible to use sand, plaster and cement to simulate rock body. It is shown that the curves between the strength of plaster sample and the sand-binder ratio are hyperbolic, but that the curves between the strength of mixed sample and the sand-binder ratio are parabola. For both plaster and mixed samples, the bake-dry strengths will decrease with increasing time. The air-dry strength of plaster sample increases with time increasing. But the strength of mixed sample changes irregularly with time increasing. These results provide useful references for rock mechanics simulation experiments.

A model test equipment had designed to go into bearing property and other influence factors about the piles with branches and plates. In contrast to the equivalent-diameter mode pile, it can be proved that there are many advantages about pile with branches and plates in bearing property and anti-settlement deformation. The test also proves that soil above the plates in some ranges gets a little side-resistance due to the existing of air face between plates and soil. In addition, because the soil under plates bring deformation together with the plates, there will be negative friction close to the bottom of plates. So it can be ignored that the side-resistance of the soil between two plates with small plate-distance against the piles. We should make great attention about it.

This paper puts forward that the displacement of the reinforced cracked wall rock has variability in direction, periodicity of destroy and otherness of velocity variety, according to the whole process observation of convergence of the analysis of rock hole poly-point displacement. The process of distortion can be divided into three phases of the sharp distortion, regulative distortion and slow distortion. The paper indicates that the displacement of rock mass may change direction in regulative distortion phase; the displacement presents periodicity according to the storing and the destroy of the energy of rock distortion; the quantity of displacement of the top is more than that of the bottom; the quantity of displacement and the destroy periodicity of the terrain reinforced with cement injection are less than that of the unreinforced terrain, the convergence of boardrooms is the displacement of certain thickness wall rock of surface layer. The key technique is to consider fully the effect of faultage construct and to design the thickness of reinforced terrain and the form of closed shells according to the stress field.

This paper hopes to reach the purpose to effectively evaluate the stability of the rockfall through the simulation of Fengdu’s Mingshan rockfall by discrete element method. We have discovered that the destructive process of the rockfall is contact with the bottom denude degree of the rockfall, and whether the bottom of the rockfall is denude or not, the mobile track of the top blocks is different from the other blocks. The results show that the Fengdu’s Mingshan rockfall is danger in truth, and must take a certain method to protect it from collapsing.

Based on the nonlinear characteristic of ANN, and on the basis of water flow FEM computation, the inversion method for seepage coefficient of dam is presented together with the observation data of water and seepage flux. In order to overcome some disadvantage of the traditional neural network, a new method of alternation and iterative algorithm based on simulated annealing applied in Neural Network is put forward. On the same initial conditions, the comparison of the new method with the neural network based on the traditional algorithm is accomplished; and the result shows the superiority and efficiency of the former one. At the same time, this algorithm is applied to seepage inversion analysis of dam, by using the inversed seepage coefficient to calculate seepage flow field. Numerical computation indicates that the method has high precision of identification and reliable inversion result, and can be applied to the practical engineering.

The Badong Yangtse Bridge is a large highway bridge across the Yangtse River, connecting the No.209 national highway to the new town of Badong County. The bridge is a kind of simply supported cable stayed bridge of 900.5 m length, of which the 388 m main span has two towers of 218 m high. The bridge’s weight is huge and the safety requirement is high, The bridge lies in the middle part of the Three Gorges where the geological condition is the most complex area. There are cliffy landform, sharply incised valley, complicated geo-structure, heavily cracked rock mass, frequent landslide and common debris flows. The slope stability has directly effect on the safety of bridge. On the basis of investigating the bridge site’s geotechnical condition, the stability of slope was simulated by nonlinear elastoplastic finite element method and block limit equilibrium principle. At the same time, the developing trend of the slope’s stability was predicted while the reservoir storing and the bridge building up. The researches show that the bridge’s weight, fluctuating water lever and earthquake are induced factors of slope’s failure. The stability of the slope is sharply decreased after the reservoir storing and the bridge building up. The slope may slide along the interface between T2b3 and T2b2. Some control measures must be taken. In this paper the effect of slope failure on the bridge was analyzed. Finally, some suggestions about existed problems are proposed.

A field dynamic compaction test of filled ground is carried out in a construction site in northwestern suburb of Beijing. Under the conditions of different blow counts and compaction energies, the subsidence of ground changes by phases. At the same time, quantitative analyzing of structure images is carried out on the samples of different compaction phases. The correlativity between microstructural parameters and the change of subsidence of filled ground is found. The test results reveal the law of controlling structure as viewed from microcosmic study during dynamic compaction.

On the basis of studying the sensitivity and the mechanism of Taizhishang landslide , this article analyzes the displacement monitoring result and the reliability of the landslide to discuss the stability of the landslide. The strength parameter and the underground water level are very sensitive to the safety factor of the landslide. The reliability of the landslide is 1.64. And the safety monitoring result of deep displacement could help us to evaluate the stability of the landslide according to the current situation of the landslide. Based on the above analysis, this article pointed out that it’s very necessary to treat the landslide.

A new landslide occurred on July 22, 2003 in FengJie, Chongqing, China. This new landslide is developed on Baiyi’an ancient landslide on which many old and new landslides exist. Because the landslide group is on the right left side of Yangtse River, once the hazard happened, it would be dangerous for not only the residents living on the slope but also the highway just through the landslide group, the docks along the river, and the normal running of the reservoir of the Three Gorges. Therefore, attention should be given to the landslides which occur possibly in the future and some measures must be taken. In this paper, the mechanism of the new landslide is analyzed after detailed surveying on the debris for the runoff and infiltration on the slope, the slope boundary, and its geological condition by drilling. Combining the analysis of the evolution of the slope boundary due to erosion by rainfall and the softening effect of the soil-rock media by infiltrated water, we conclude the main reason of the occurrence of this landslide is that the foot of the slope had been continuously eroded by the water-flow down from the up-reach during rainfall. The existence of the deep gully also provided well geological condition for continuing sliding. Though there is no life loss in the event, the distance between the resident house and west boundary of the slope is less than 10m, and some houses have been damaged with long cracks. Measures should be taken on the slope after slide to prevent larger hazard from happening, especially for the security of the local residents. A primary plan has been presented in this paper. It should note that these measures are identical with the scheme for treatment of whole Baiyi’an landslide group, which has been proposed in existed literature.

During excavation of deep foundation pit, a lot of dewatering measures are adopted to ensure that the foundation pit is dry and the construction is convenient. The dewatering of foundation pit can cause the seepage outside and inside the foundation pit, and result in the changes of groundwater, earth pressure and mechanical properties, and directly affect the earth pressure acting on supporting structures. There are two kinds of method to calculate earth pressure, respectively, the calculation of separating water and soil from earth pressure and the calculation of mixing water and soil into earth pressure. Therefore, It is very important that the proper dewatering model should be selected and the seepage is considered when the supporting structure is designed in the process of dewatering of foundation pit

Shear strength properties of slip soils are important for landslide research and control design. Based on the review of presently available literature, especially some typical investigations, the paper summarizes their major research advances, covering areas, methods and achievements. The five feature strengths, i.e. peak shear strength, residual strength, full softened strength, mobilized strength and long-term strength, and their related microstructure characteristics are the basic research elements; the field and laboratory tests are the basic research methods, while back analysis and theoretical analysis are secondary; achievements are reached mainly in the area of shear-induced microstructure characteristics, feature strengths and their relations. Residual strength research is discussed in detail, especially its influencing factors and estimations. Finally, the paper indicates some aspects to be strengthened, including special slip soils, e.g. slip soils with gravel, development of new testing and analysis method and the proper application of back analysis method, etc..