The concept of representative value of the dynamic stress concentration factor is proposed to describe the degree of dynamic stress concentration of underground openings under seismic loading. And the representative factor is employed to reflect the seismic response characteristic of underground openings. Based on explicit finite difference method, the relationship between five key factors: (1)acceleration amplitude of seismic wave, (2) overburden depth, (3) rock grade, (4) liner thickness and (5) concrete grade, and the representative factor has been investigated. It is shown that all these five factors appear approximate linear relationship with dynamic stress concentration factor. Accordingly, formulas of seismic safety assessment have been developed for both lined and unlined underground openings and a safety assessment method for underground engineering in rock under seismic loading has been proposed. The proposed assessment method is therewith applied to evaluate the safety of Xiluodu underground cavern groups subjected to Tangshan aftershock. It is demonstrated that the proposed method draws similar conclusions to Dowding-Rozen and Sharma-Judd’s methods. It also reveals that this method gives a relatively conservative assessment results.

Field survey, systematic sampling and laboratory tests were conducted to study the weathering mechanism of earthen architecture taking the Jiaohe Relics site, Xinjiang, China for example. Particle size analysis, X-ray diffraction and chemical analysis of soluble salts illustrate that surface crusts are characterized by finer particles and lower soluble salts contents compared with the host soil. Temperature monitoring by IR thermography camera and thermal sensors shows that thin crusted layers response greatly and quickly to the environmental temperature change. It is concluded that the local saturation and slurry film generation due to rainfall are mainly responsible for the formation of surface crusts; and the crust will be subsequently detached by wind erosion and expansion-contraction induced by the change of temperature. Surface crusted layer prevents the wall from weathering to some degree at its earlier formation stage but tend to accelerate the deterioration of the earthen architectures in the long term considering that Jiaohe site suffer from strong sandstorm and strict weather condition.

According to analyzed characteristics of blasting enhanced permeability in deep rock mass without free surface, based on the similarity theory of the model test, the similarity law of model test of blasting enhanced permeability in deep rock mass without free surface is studied. Based on the deduced similarity criterion of model test, combined with engineering geology and hydrogeology of a low-permeability sandstone-type uranium deposits in Inner Mongolia, China, the similarities of geometry conditions and boundary conditions and exploding load conditions and material conditions are implemented through theoretical analysis and experiments, which lays a good foundation for model test of blasting enhanced permeability.

In clayey soil, soil particles generally possess negative ions, and form an electronic field nearby the particles. With the function of electronic attraction force and Brown (thermal) movement force, electronic attraction force is much stronger nearby the surface of soil particles, ions and polar molecules are closely attracted to particles surface that forms a close layer around the particle. Outside this layer, the electronic attraction force decreases as the distance increase from the surface of the particle, and they form a dissipative layer. Ions in the dissipative layer and negative ions in the soil particles surface form diffuse double layer. Based on diffuse double layer theory, when the distance between two clay planets is known, the seepage force can calculate using the ion concentration at the middle plane between two planets. In the same way, the ion concentration at the middle plane between two planets is known, the distance between two planets can be calculated. The soil water characteristics of densely compacted Gaomiaozi bentonite has been obtained using osmotic and vapor phase techniques under free swelling conditions. At the same time, the volume change behavior of Gaomiaozi bentonite under unconfined conditions has been calculated using diffuse double layer theory. Comparison between calculated results and test data has also made. Results show that there is a good consistence between calculated results and testing records for the volume change of densely compacted Gaomiaozi bentonite under low suction.

A novel continuum mechanics-based model is presented to overcome the one-dimensional limitations of Gibson’s finite-strain consolidation theory. The second Piola-Kirchhoff stress and Green strain are used to replace Lagrangian stress and void ratio respectively in Gibson’s theory. The proposed model can take into account of both the geometrical nonlinearity and the material nonlinearities of soil’s compressibility and permeability; and it has the advantange of multi-dimensional generalization. Based on the experimental data from engineering practice, the finite-strain coefficient of consolidation and the coefficient of convection are investigated. The results show that the convection rate decreases with the increase of strain, indicating that the dead weight effects tend to diminish during finite-strain consolidation process.

The chaotic characteristics of creep deformation of rock are studied based on rheological model method and test method; and the analysis of evolution process of chaotic behavior and the route to chaos as well as the occurrence condition of chaos are given. The engineering applications of the two methods and the theoretical and practical meanings of its parameters are also discussed. The results show that the development of rheological deformation of rock can be described as that: order-chaos(disorder)-order. Based on the property of development of creep deformation of rock has chaotic characteristics, the conclusion of controlling the stress level of rock creep system is the main method of avoiding chaos occurrence which is presented in the end.

By using an improved direct shear creep apparatus, exploration of effects of adsorbed water on rheological characteristics of soft soil is performed; and rheological characteristics of two groups of dried clay samples with different contents of kaoline and bentonite, respectively, and one sand sample are tested under the same test conditions. The compasions between current test results and data obtained from recently creep tests show that the adsorbed water is an important factor on rheological behavior of soil; the viscosity coefficient of dried clay is higher than that of wet clay, which compositions is the same as the dried clay; and the viscosity coefficient of sand is also higher than that of the wet clays; that is, the rheological strain resistance of the dried clays and sand is relatively greater than that of the wet clays; and the rheological phenomena of the formers are less obvious than that of the latters. Based on the data obtained from laboratory expriments, the substance bases of rheological characteristics of soft soil are explored. And the definition of “rheology substances” is proposed. The analyses of test results indicate “rheology substances” are responsible for rheological characteristics of soft soil and are the primary substance bases of soft soil rheology. The physical description of rheological mechanism of soft soil is presented, which is corresponding to the mechanical properties of “rheology substances”.

Aimed at the controversy on the results of ground settlements predicted both by large-strain and small-strain methods, the significant concepts of finite-strain stress and strain measures, constitutive relations and related parameters etc., are investigated. Based on fundamentals of continuum mechanics, the large-strain settlement formula in respect to Green strain, Almansi strain, and natural strain are presented. The large-strain constitutive relationship of soil compression is proposed with respect to Euler stress – Almansi strain pair and Euler stress – natural strain pair. A transform method between the tangent volume compressibility coefficients using large-strain and small-strain schemes is put forward. The theoretical analysis and the corresponding case study show that the computational settlements by large-strain and small-strain methods should be identical in the case of strictly following the presented transform method; otherwise the value of large-strain settlement might be over or under that of small-strain method. The transform method can also provide new reference for determining reasonably the large-strain constitutive parameters.

The cell of foundation soil is taken notable impact on dynamic deformation and dynamic strength behavior under rotation of principal stress axes by cyclic wave load. The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic coupled vertical and torsional shear test by different cyclic stress paths. Through a series of tests on saturated clay, the dynamic deformation, stress-strain relationship and dynamic strength are systematically investigated under rotation of principal stress axes. It is found that stress-strain relation of shear stress and normal stress has obvious distinguishing between consolidated-undrained and unconsolidated-undrained coupling test by comparing the experiment data. Meanwhile, it is observed that stress-strain relationship curve gradually loosen and the secant modulus decayed as the cyclic number increased. Moreover, it is shown that the dynamic strength under major dynamic shear stress is less than the one under major normal stress by different elliptical stress paths. By conducting experiments on clay with changes in stress paths, the mechanical behavior can be investigated on which the establishment of proper constitutive model for soil is based.

Wide contribution of layered rockmass cannot be avoided in underground construction. Based on the Gonghe tunnel in Yuxiang Highway a physical model for layered rockmass is made adopting elastobrittle simulated material which is developed independently. Loading through the large scale real triaxial geotechnical engineering testing machine, the configuration trait of secondary stress and failure mechanisms of layered rockmass tunnel with low inclination angle are presented. Various failure mechanisms present in various place via the strain in surrounding rock, inner video and failure configuration around the tunnel. The test provides a quantitative evaluating index for safety storage with overload coefficient. The failure in the test is consistent with the practical tunnel which validates the anisotropic model and provides a foundation for the research on reinforcing mechanism and reinforcing design of tunnels in layered anisotropy rockmass.

Based on matter-element model and the classified analysis theory, an extension clustering prediction method for assessment of seismic liquefaction of saturated sandy soil is proposed. In the method, Eight influence factors on seismic liquefaction, including seismic intensity, epicenter distance, the depth of sand, groundwater level, the blow counts of standard penetration test, mean diameter, coefficient of uniformity, cyclic shear stress ratio, are adopted to establish the classical and limited matter elements, and the dependent function of matter-element and extension set is applied to establish prediction model for seismic liquefaction of saturated sandy soil. The prediction results of the grades of seismic liquefaction of saturated sandy soil can be obtained by means of clustering analysis. The results show that this model can reflect the liquefaction potential of saturated sand objectively and truly; therefore, the extension clustering prediction method is effective and feasible in evaluation of seismic liquefaction of saturated sandy soil.

Considering the increase of speed-trains in existing railways of China, i.e., passenger train will run at speed of 200 km/h and heavy truck at speed of 120 km/h, thus the dynamic responses of railway subgrade with train speed increasing are studied. Firstly, the coupled dynamic model of train-track-subgrade is applied to calculate the interaction force between wheel and track. Subsequently, according to nonlinear numerical analysis, the dynamic responses of subgrade are analyzed with different train groupages and running speeds, including the dynamic subgrade stress, displacement and acceleration, and their distribution and attenuation in subgrade. Moreover, relationships between the design parameters of subgrade and its dynamic responses are also studied. Field measured data were used to verify the numerical results. It is found that the influence of train speed on subgrade dynamic responses is limited, whereas the axial load of train affects subgrade greatly; there is an optimum stiffness for strengthened subgrade(i.e. 120 MPa). With the thickness of ballast increasing, the subgrade dynamic stress reduces linearly, but dynamic displacement and acceleration have a negligible change.

There are more and more reports of construction on municipal solid waste landfills. But there are no systematic experiences and perfect design method for improvement of municipal solid waste. According to statistical results from national municipal solid waste landfills, artificial municipal solid waste was made. The unconfined compressions of artificial municipal solid waste were tested in under-degradation or in-degradation or past-degradation, mixed with cement 25 %, 35 %, 45 % at different maintenance periods. It is obtained that hardening stress strain curves and the strength law of artificial municipal solid waste mixed with cement versus maintenance period and cement content as well as degradation phase. The test results show that the organic constitute in artificial municipal solid waste can reinforce and weaken the artificial municipal solid waste mixed with cement. There are different strength characteristics of artificial municipal solid waste mixed with cement at different degradation phases. Only municipal solid waste at past-degradation can be better improved. It is suggested that the cement content is more than 35 %.

Aiming at the difficulty to treat the stratum-absence and stratum- reversion situation, some researches on the method for complex stratum-line based on drill hole database are carried out. On the consideration of the single stratum continuity and the mutual influence of strata, a new algorithm is proposed to search the reference points of stratum boundary, which can deal with six special situations of stratum-absence and stratum- reversion. Meanwhile combined with cubic spline interpolation function, the second arithmetic modifying the point position is used to smooth the Stratum-line. The results of applying this aforementioned method to the digital profile mapping of Guangdong Meihe Expressway Project, indicate that the mapping precision is consistent with the maps from the investigation reports, and could provide some reference and guidance for the engineering design and construction.

Particle breakage of coarse granular aggregates changes its structure directly, influencing its dilatancy and friction angle. In the course of shearing, normal stress and shear stress do work on volume strain and shear strain. This energy is transformed into particle elastic energy storage, particle friction energy consumption, work done by particle dilatancy and particle breakage energy. The accurate measurement on breakage energy of coarse granular aggregates in the course of shearing aims that it provides a method to analyze the particle breakage influence on constitutive relation in the perspective of energy, creating conditions for development of coarse granular aggregates constitutive relations considering particle breakage. The breakage energy of coarse granular aggregates in the course of shearing is calculated by analyzing the results of the coarse granular aggregates in triaxial compression test. The results indicate that the breakage energy during triaxial tests is mainly influenced by confining stress and friction coefficient.

A rheological model of equivalent simulation has been presented by considering the lining’s action of controlling shear and crack on joints and fractures; and on this base, the constitutive equation of jointed rock mass reinforced by shotcrete lining has been deduced; so the equivalent mechanical model of jointed rock mass reinforced by shotcrete lining has been established. When a structure is analyzed by using this mechanical model, joints or shotcrete linings need not to be discreted grids, and are equivalently simulated. If the number and direction of joints or the thickness of shotcrete lining are changed in the analysis of structures, the finite element mesh will keep unchanged. In this way, the pre-treatment workload is reduced and the analysis of the large scale rock structures becomes relatively convenient. Finally, this mechanical model has been verified by examples－not only effective in the simulation of the mechanism of shotcrete lining similar to discrete model, and convenient and practical for the complicated structures similar to equivalent simulation; it will be of good practical application.

Using the frozen soil uniaxial compressive apparatus combined with electrical resistivity observation for whole process, a series of uniaxial compressive tests under different environmental temperatures are performed for the clay in Beilu River with an initial water content of 17.8 % and dry density of 1.71 g/cm3 under a loading strain rate of 1 mm/min, in which the complete testing data for the stress -strain curve and the associated electrical resistivity-strain curve are obtained. The experimental results indicate that , , are increased with decrement of the temperature T and they are changed synchronically. The frozen soil performs highly pressure-sensitivity, with the increasing of stress, the procedure of electrical resistivity includes three stages: decreasing stage, balance stage and sharply increasing stage. There is the linear relationship between the largest tangent modulus and temperature. , , show sensitivity to temperature, the value of , , is minimum when the temperature is -15℃. The ductibility of frozen soil is enhanced and its brittleness is reduced; at the same time , , are increased with the decreasing of the temperature, when ℃.The frozen soil has opposite characters when ℃.

By means of the improved SHPB with axial pre-pressure and confined pressure, a series of experiments on sandstone are carried out to research the mechanical behaviors of rock during the course of exploitation of resources in deep. The experiment includes some tests under triaxial static-dynamic coupling loads with fixed confined pressure or fixed axial static pressure. The results from tests under fixed confined pressure show that both static-dynamic coupling strength and elastic modulus are increased at the elastic stage and decreased at failure stage with increasing axial static pressure. The maximal strain rate and average strain rate are decreased at the elastic stage and increased at failure stage. When the axial static stress reaches to 80% of the corresponding static triaxial compressive strength, the static-dynamic coupling strength will be up to the maximum. On the condition of fixed axial static pressure, the static-dynamic coupling strength and elastic modulus are increased and the average strain rate is decreased with increasing confined pressure. It is found that the maximal strain rate is not obvious related with the confined pressure.

Based on the characteristics of whole stress-strain curve of SFRC of different steel fiber volume ratios of laboratory test, the change of damage variable and the necessity of considering the influence of the damage threshold in developing the damage constitutive model of SFRC are discussed. Then, according to continuum damage theory and the statistical approaches of strength, the introduction of damage threshold based on the traditional Weibull random distribution of two parameters, the damage constitutive model of compression process of SFRC considering the damage threshold is proposed. This model can reflect the linear-elastic characteristics of SFRC deformation in low stress level or small deformation. Then when the value of damage threshold is determined by experience, the expression of two other parameters of Weibull random distribution is deduced through the geometric conditions of the whole stress-strain curve of SFRC. Finally, the analysis results of MATLAB contrast with uniaxial compression test results, it is shown that this model correctly reflects the stress-strain relation under uniaxial compression; and the value of damage threshold is discussed.

With the construction of the Three Gorges Project, many natural and artificial rock slopes will be drown, then the stability of these slopes will reduce. The comprehensive factors of the water pressure, water leakage, water impaction and water corrosion will endanger the stability of underwater rock slope. Based on the model tests of the stability of soil slope and the analysis of the rock slope by the finite element method, the model tests of stability and damage mechanism of underwater rock slope are carried out, including the ascending and descending water level test and the wave impaction test. Some significant conclusions can be drawn from the model tests by measuring and analyzing the stress distributions with different structural angles (30° and 50°) slopes in the artificial wave tank. The rock slope can be divided into three regions in which the stress variation rule is the same. The results show that the stress concentration occurs to the slope toe, where failure begins, plastic zone develops upwards along the discontinuity, which is different from the downward failure mode happened to general slopes; it’s also concluded that the effect of the wave on the slope discontinuity decreases with the slope angle.

Detailed studies were conducted on shear peak strength and residual strength of overconsolidated saturated clays at different overconsolidation ratios, normal stresses and shear speeds by employing ring shear apparatus. The residual strength behaviors before and after applying cyclic loads were also investigated. Test results indicate that: overconsolidation ratios have obvious effects on shear peak strength and residual strength of overconsolidated clays; under the same shear speed, shear displacements reaching residual state depend on the present stress state, not being relevant with stress history; with shear speed becoming faster, both peak strength and shear displacement reaching residual state increase, while shear speed has no effects on residual stress; Residual strengths after applying cyclic loads decrease differently, the largest decrease up to 12.2 %. When shear surfaces are irregular shear bands, residual strengths increase after applying cyclic loads.

Soil squeezing effect induced by DCM (deep cement mixing) pile has an impact on tunnel deformation while the cement mixing pile is used to strengthen the ground around tunnel. Four lateral load models are proposed and verified based on numerical simulation and measured data. Soil squeezing effect is simulated by the finite element method using the lateral load model. The ground deformation ,tunnel deformation concerning creep effect are analyzed with respect to different construction sequences. The results show that construction sequences have a great effect on ground deformation and the deformation of the tunnel when DCM pile is constructed，but tunnel deformation concerning creep effect is small.

Digital image processing technique developed by Dalian University of Technology is used to perform triaxial consolidation tests in order to study the collapse deformation of unsaturated remolded loess. The volumetric changes of samples can be accurately measured in consolidation process by the untouched measures technique. Relations between axial strain, radial strain, volume strain and time and relation between volume strain and stress are examined. Under the condition of fixed water content, the relationship between axial strain, radial strain, volume strain and time can be expressed in hyperbolic model, in which the parameter that stands for the final deformation depends on the uniform consolidation pressure.

The plane radial flow and ball-type centripetal flow permeation grouting models based on mechanics of seepage flow are deduced. Then one of the corresponding formulas in this paper is compared with Maag's formula based on engineering example. The computation results preliminarily show that diffusion time of Maag's formula is less than the practical time, but the formula of this paper is more accordant with reality. Finally, the influence of diffusion radius on grouting parameters is discussed. The results show that the diffusion radius is sensitive to the grouting parameters and the results in the use of Maag's formula are basically keeping with those in the use of the formula of this paper.

An aseismic modeling test of the entrance of two-track tunnels is carried out in laboratory, in order to learn about the dynamic response of tunnel-liner and the effect of seism-reducing layer on tunnel-liner security and rock-slope stability during earthquakes. In this modeling test, two cases with and without seism-reducing layer respectively, are executed to analyze the behaviors of seism-reducing layer. The measured results show that: (1) the seism-reducing layer can reduce the destruction degree of surrounding rock, exhibiting no effect on their destruction mode; (2) the seism-reducing layer exerts more effect on the stress distribution under earthquake action and diminishes the force loaded on tunnel liner to some extent; (3) for the tunnel entrance with unequal mileage, the tunnel-liner of long mileage tunnel is sustained more complicated stresses around the cross-section containing the tunnel entrance with short mileage, and the seism-reducing layer is able to relieve the destruction degree of tunnel-liner near that cross-section effectively.

Particle breakage of calcareous sand occurs at lower stress level, and it results in stronger acoustic emission (AE). Triaxial shear tests on calcareous sand at Yongshu reef of Nansha islands are carried with different confining pressure, initial pore ratio and grain gradation, at the same time AE signals from sand are monitored. Test results show when confining pressure increases or initial pore ratio decreases, deviator stress peak value increase gradually, but AE is the strongest or weakest at some confining pressure or pore ratio limit individually; if the gradation of calcareous sand is poorer, its AE is weaker at the beginning of test; and deviator stress peak value is also smaller.

It is generally realized that earth pressure will change with the deformation and displacement of foundation pit. But at present the design of straight brace does not almost consider earth pressure changing with displacement of foundation pit. Firstly, the researches and achievements on the nonlinear relation of earth pressure and the displacement of foundation pit are summarized. Secondly, the rules on earth pressure changing with the displacement and movement of the side of foundation pit are discussed. On the basis of the present researches and the change rules on earth pressure changing with displacement of foundation pit, new formulas of axial force and deformation of straight brace considering the rotation or movement of the side of foundation pit are presented. At last, the curves of axial force and deformation of straight brace changing with some factors are obtained. Those factors include different initial displacement of foundation pit, supporting location of straight brace, friction angle of soil and retaining structure, resultant force action point of earth pressure. Conclusions can be drawn as follows from these curves: axial force and deformation of straight brace will diminish with the increase of displacement of foundation pit, supporting location height of straight brace and friction angle of soil and retaining structure. The height enhancement of resultant force action point of earth pressure will improve axial force and deformation of straight brace. But the initial displacement of the side of foundation pit has no influence on axial force and deformation of straight brace.

The primary goal of this research is to solve the deformation problem of the bucket foundation on soft clay strata under cyclic load. Firstly, by cyclic model test, the failure characters of bucket foundation under static and cyclic load are studied. Secondly, unconsolidated undrained cyclic triaxial tests of the soil used in the model test are conducted under different static and cyclic loads to study characters of cyclic accumulative strains; and the relationship between strains and the relative factors is established. Finally, the model tests are simulated by using the finite element method. The cyclically accumulated deformation is equalized as a process of creep; and the deformation is calculated using ideal elastoplastic plus creep model. Then the calculated result is compared with the test result. It is concluded that the deformation of bucket of bucket foundation on soft clay strata under cyclic load is similar to the creep under static load, and the cyclic accumulative deformation can be calculated using this equalized method.

Calcareous sediments generally consist of the remains of marine organism，which tend to crush relatively easily under load, compared to terrigenous materials. Based on the data of triaxial shear tests carried out on calcareous sand taken from the South China Sea, the influences of the particle breakage and dilatancy on shear strength of calcareous sands are discussed and analyzed. The results indicate that the particle breakage and dilantacy have significant effect on the shear strength of calcareous sands. The effect of the dilatancy on the shear strength is more serious than that of the particle breakage under low confining pressure, while with the confining pressure increasing, the effect of the particle breakage increase and that of dilatancy decrease. When the confining pressure attained to some extent, the particle breakage and its effect on shear strength will diminish.

Based on statistics theory, Mahalanobis distance discriminant analysis model for prediction of sand soil liquefaction is established, including the main six factors that have great influence on sand soil liquefaction as follows: seismic intensity, epicenter distance, groundwater table, sand depth, blow number of standard penetration test, duration. Linear discriminant function is obtained through training a large set of sand soil liquefaction samples. Then the model is applied to the practical engineering. The results show that the prediction model of diatance dicriminant analysis has excellent performance,high prediction accuracy, and might be referred to as an effective technique for prediction of sand soil liquefaction.

Based on the following two reasons, applying static bolt-pile for construction of basement in existing buildings is practicable. (1) The gravity of the existing building can be used as reaction-force to drive piles; (2) As the temporary underpinning components, the driven piles can be used to support the existing building, thus the soils under the building can be excavated. In clay, when all piles are driven to the design elevation and the excess pore pressure is dissipated, the soil under pile caps can be excavated. In sandy soil, settlements of the existing building can be controlled by controlling the speed of driving piles and excavating soil, thus driving piles and excavating soil can be constructed at the same time. After the soils around the pile is excavated, stability analysis of the pile is done according to a high–caps pile model with a major unsupported length. Resistance in driving pile process is determined by using the dynamic penetration results of soil. The number of the static bolt-piles is calculated synthetically by the loads of service and construction processes and the results of pile stability analysis. According to punching shear bearing capacity before interface slip of new-to-old concrete, the pile cap design has sufficient safety. Punching shear strength is held by some slanting concrete columns; while the tensile force is created in bottom of the pile cap. The differential settlements of piles cause structure additional internal forces which influence safety of the existing building. Calculating the differential settlements by layer-wise summation method should consider factors as following: additional stress increase induced by gravity of piles and concentrated loads on the top of piles, as well as additional stress decrease because of excavating soils.

Taking the Wuhan Yangtze River tunnel as an engineering background, the internal forces distribution of segment lining structure with different segment widths and different ring joint shear stiffnesses is analyzed by 3Dshell-spring model and compared with the results achieved by beam-spring model. The study shows that: the maximum bending moment on the entire ring always occur on the edge of segment; the ring joint shear force has an great impact on the edge of segment and less in the middle of segment; when the ring joint shear stiffness is non-infinite, the maximum bending moment on the edge of segment calculated by shell-spring model is slightly larger than the results by beam-spring model; and these results almost equal when the joint shear stiffness is infinite; the maximum bending moment in the middle of segment calculated by shell-spring model is between the results by beam-spring model with stagger-jointed and those results by beam-spring model in sequence, and tend to the results in sequence with the segment width increased; when the segment width is large, the maximum shear force between rings calculated by beam-spring model is unfit for shear design of the ring joint.

In light of the existing problems in the development of soil-cement mixing piles, T-shaped bidirectional soil-cement deep mixing columns and their construction technology are introduced. Construction quality test results show that the quality of T-shaped bidirectional soil-cement deep mixing columns are better than conventional soil-cement mixing piles. Compared to conventional cement mixing piles composite foundation, the bearing capacity of the pile foundation and composite have improved greatly. Through the observation of the analysis of test site result, the engineering properties and economic benefits of the method that T-shaped bidirectional soil-cement deep mixing columns reinforces soft ground superior are demonstrated.

The swelling-shrinking deformation, deformation modulus and permeability of expansive soil are tracked and measured in Nanning, Guangxi considering the effect of atmosphere. The test results are just as follows. Firstly, a low rainfall may lead water content and swelling state to the limit value, and the influence depth of infiltration is finite while raining. Secondly, the deformation modulus is decreased with the increase of water content following the forms of power function. Finally, when the water content is low, the fissure is developed and the permeability is improved greatly; meanwhile, the permeability is also strengthened with the vegetation covered, which is useful to recognize the disastrous mechanism of expansive soil slope.

The need to build embankments on soft clay deposits is widespread, including railway and expressway embankments. The difficulties in constructing embankments on these deposits are well known. The permeability of soft subgrade is usually low, so that construction is generally performed under undrained conditions, as a consequence of the low undrained shear strength of soft clay. The classical design of an embankment is often based on a limit equilibrium approach, in which the deformation factor can not be taken into account, so that the finite element method which can take deformation and stability into account becomes an effective method. Based on the in situ test data of Lianyungang railway embankment built on soft subgrade, the failure behavior and limit height of embankment are analyzed under the plane strain condition by using large deformation finite element method and Mohr-Coulomb model. And the numerical results analyzed by finite element method are compared carefully with the in situ test data. The results show that the limit height and failure behavior of embankment can be obtained by using the large deformation finite element method.

The mass data in whole process of physical model test were real-time recorded; and the implementing mechanisms, reinforcement efficiency, construction technology of new horizontal flexible reinforced grouting technology were studied with physical model test in field. This paper focuses on the test design, manufacture scheme of model, testing method and research methods of experimental research. The test results show that the new horizontal flexible reinforced grouting technology contains enormous advantages including easy processing, effectiveness, and development and utilization value. It is indicated by the results of the experiment that the test results combining with the theoretical calculation have the guiding meaning for modifying the designing parameters. Meanwhile, the test results and construction parameters of the new technology can be used in real design and similar engineering for the test conditions of model test are basically in consistence with the conditions of actual operation.

Soil nailing wall which is developed to protect excavation in soft ground is applied to definite excavation depth. Soil nailing protection structure has the limit excavation depth, namely. The method of confirming the limit excavation depth of soil nailing protection structure is put forward; the limit excavation depth of soil nailing protection structure is studied based on the silt foundation. The influences of soil nailing wall slope, surcharge, physico-mechanical properties, and soil nailing diameter on limit excavation depth are studied. For the excavations in the silt and mucky soil grounds, the limit excavation depths are 5.0 m and 6.0 m respectively.

Estimation of the post construction settlemen is one of the most critical problems in expressway. Exponential curve method and hyperbola method is the most common method in the previous research; but the estimation results from the former model tend to be the smaller and those from the latter model tend to be larger. Based on analytical results, a kind of hyperbola model is proposed that the relationship between the settlement rate and the settlement seems as half-cube nonlinear behavior. Theoretical analysis and engineering case application prove that the estimation results of the new model are placed in those of two kinds models in common use; and they are close to the average. It is shown that the reliability of the estimation results is a little higher than the other two models.

The tests on compression and uplift capacities of two fabricated steel foundations with different base sizes are carried out; and these load-deformations are investigated. Based on the strain-developing of steel and the observation on failure behavior of steel foundation and soil, the deformation and failure behavior of the fabricated steel foundation are investigated; and the shear failures of soil have appeared for the two foundations. Lastly, the calculating theory of compression and uplift capacity is proposed, in which the effective bottom area of foundation is used for calculating compression capacity and the soil inside spread angle is considered for calculating uplift capacity. Besides, it is proposed that the internal friction angles of different soils can be adopted as its spread angle; however, the spread angle under groundwater can be regarded 0 º. This research provides the important data for the theory of capacity calculating, designing method and engineering applications of this kind of foundations.

The settlement of foundation in a heap of the ore-port is calculated by specification and one-dimensional consolidation theory. Based on settlement data measured in field，compressibility modulus and consolidation coefficient of soil layers are obtained by back analysis method. Post settlement is also calculated and predicted with the proved compressibility modulus and consolidation coefficient of soils, then the time and quantity of the next-stage loading is obtained. By contrast with traditional methods predicting settlement, the result is much more reliable, this method is good at reflecting mechanics of consolidation of soils. The method can provide references for design and construction of other such project.

The orebody No. 3 of a gold mine had been exploited by using openstope method. The production halted on December 4, 2006 because of the collapse accident of stope. In order to recover production and ensure the productive safety for the future, it is necessary to analyze the cause of caving and find out the actuality of fill-up. After geologic and stope investigation of the orebody No. 3, the cause of collapse is analyzed. Then the geophysical exploration technique, electromagnetic method, is used to detect the status of quarry. The exploration results not only open out the fill-up of dead zone, but also find out the abnormal zone of mineral deposit. It will be the evidence of recovery production and is recommended as reference to the future design.

Base on large number of researches before, and according to traditional SMR（slope mass rating）, whose shortage is not consider slope weak rock mass interbed influences the slope rock mass evaluating result, the adjusting weight item of intensity difference is introduced. Through investigating 80 redbed soft rock slopes in Southwest China area, it is shown that the SMR modified by the difference of rock character is betten than the traditional SMR in practical situations; so that the modified SMR is more reasonable using in redbed soft rock slopes appraisement.

stability is influnced by many factors.It is necessary to study the sensitivity of influence factors of slope stability. By using reasonable computational model, and grey correlation grade method to analyze the main influence factors of the high loess slope stability in Baojixia Water Division Project. The results indicate that the angle of internal friction and cohesion are the principal factors influencing the slope stability; and by the method of orthogonal test, the results indicate that the influence of earthquake is also significant on the slope stability. All the results show that the angle of internal friction and cohesion are the principal factors influencing the slope stability; on the basis of which shearing strength should be correctly and reasonably selected. And the influence of slope height and earthquake also should be considered. Therefore, the study can provide reference for high slope of loess design, operation and management.

The water flow problem in fractured rock mass, in which the fracture aperture is distributed randomly, is simulated by using finite element method. The fracture apertures of model elements are generated randomly according to the average value and standard deviation of fracture aperture; and material parameters and element properties are changed by ANSYS parameter design language. The equivalent transmissivity of fracture is computed according to flow flux through some section computed by FEM and Darcy law; and the relationship between the equivalent transmissivity and roughness of fracture is presented. The numerical simulation investigation shows that compared with straight and smooth fracture, the equivalent transmissivity of fracture with rough surface will decrease slightly. For the investigated fracture model with 0.5 mm average aperture, the equivalent transmissivity of fracture with different standard deviations of fracture aperture changes only 5 % while the standard deviation of fracture aperture fluctuates from 0.01 mm to 0.2 mm. Traditional governing equation of water flow can not accurately depict the transform principle of water through rough fracture because the definition of pressure water-head in the equation ignores the velocity item.

A 2D model for coupling thermo-hydro-mechanical-migration and the relevant FEM code made by author is extended to 3D. From the viewpoint of methodology study, a 3D numerical simulation for the coupled thermo-hydro-mechanical-migratory processes in a simple model of geological disposal of nuclear waste, which is taken for example, is carried out. The distributions and changes of the temperature, saturation, nuclide concentration, pore pressure, displacement, normal stress and flow velocity in the near field are investigated. It is considered that the computation results are in keeping with the regular pattern. Finally, some conclusions are drawn：in order to simulate the migration of radioactive nuclide accurately，it is necessary to analyze temperature field，seepage field，stress field and nuclide concentration field by coupled method；higher compressive stresses will appear in the neighborhood of disposal pit wall after several decades from the embedment of nuclear waste；in buffer layer the period during which nuclide concentration reaches relative stabilization is much longer than those during which temperature and saturation reach relative stabilization respectively.

This paper proposed a new chemo-plastic constitutive model for partially saturated soils on the basis of Hueckel’s chemo-plastic model for saturated clays and Gallipoli’s model for partially saturated soils. The implicit integration algorithm for this model is also presented. The chemical softening effect and variation of suction are taken into account in the present algorithm. The program code for the algorithm is developed based on the framework of finite element program for partially saturated porous media. The new program can be applied to numerical simulation for mechanical behavior of partially saturated soils with chemical pore fluid and chemo-mechanical coupled nonlinear analysis in geotechnical engineering problems.

Based on the accurate determination of structural sequence and framework, a set of thinking and approaches were explored which includes establishing structure model, determining boundary conditions, selecting mechanical parameters and hazard prediction criterion of rock masses, calculating the value of paleo-tectonic stress, and predicting hazard areas and safety island. The plane stress model and three dimensional model were established by using of finite element method. Paleo-tectonic stress acted on Chengzhuang mine were simulated from its loading way and loading value. By the joint of rock of earth surface and coal bed ,we can calculate its internal frictional angle and ability of resistance to distortion, and obtain the critical region, risk region and safety region of ground surface and coal seam 3#. Combined with the structural features of joints, faults, folds, and subsided columns of studying area, we can integrate forecast the hazard zonation of the mine. The prediction results reveal that there are two large stage paleo-tectonic movement at Chengzhuang Coal Mining Area of Jincheng in Shanxi province; first with the north-south direction and later with west -east direction, first loading 60 MPa toward west-east and later loading 110-180 MPa toward north-south, the possible hazard area separated into eastern zone and western zone. The conclusions have important significance for the prediction of coal rock mass stress concentrated zone and gas outburst area.

The finite element analyses of a concrete faced rockfill dam (CFRD) with and without extrusion-sidewall are carried out using a simplified equivalent numerical model of extrusion-sidewall. Furthermore, a special condition of a CFRD with extrusion-sidewall only on the upper half is considered to investigate the effect of the form of extrusion-sidewall. The analysis is focused on the slab face stress and deformation. Calcalation results show that the distribution of deformation of dam and slab is insignificantly affected by the extrusion- sidewall, and the stress of slab and the settlement of the peripheral joint along the face edge are changed because of the adoption of extrusion-sidewall. The extrusion-sidewall has insignificant effect on the safety of the dam.

Combining the hybrid boundary node method (HBNM) and the dual reciprocity principle, a truly boundary-type meshless method- dual reciprocity hybrid boundary node method is presented for solving dynamic problems. It is used to numerically find the solutions of a crack of finite specimen under an impact load. The solution is divided into particular solution and general solution. The general solution is solved by means of HBNM; and the particular solution is approximated by using radial basis functions (RBF). The inner nodes are just for RBF interpolation, which is not influence that the present method is a boundary-only method. The basis functions enrichment in moving least squares (MLS) are presented for simulating the singularity of the stress field on the tip of the fracture. The presented method has many advantages such as simple post processing and higher accuracy. Numerical examples have shown the stability and the validity of the presented method.

Pointed to being built highway slope, the slope displacement with the effect of bias tunnel shows to vary because of cutting slope, rainfall and construction. The combined stability between cutting slope and bias tunnel in mountainous area is analysed by the finite difference program FLAC3D. The combined stability are studied and the scope is ascertained in slope without cutting, reinforcement and rainfall, according to the displacement contours and the distribution character of the pore water pressure and shear failure region on base of plastic mechanics, rheologic mechanics and seepage mechanics with a modified viso-elastoplastic creep model. The comparison is carried out to reinforce slope, which the combined reinforcement is accepted as double antislide pile. The results show that the testing displacement data are consistent with numerical calculation. Simultaneously, the creep model is felicitous to characterize the rheological behaviour of rock and soil.

As a semi-empirical rule for estimating shear strength of integral rock or jointed rock masses, the Hoek-Brown failure criterion has been one of the most useful criteria in forecast and stability analysis of rock masses strength. Three main kinds of rock materials are provided as the representative analysis; the sensitivity degrees of Hoek-Brown criterion parameters to the safety factor of rock slope are searched using the finite difference method and sensitivity analysis method. The research indicates that geological strength index(GSI) is the most sensitive to the rock slope stability, comparing to the material constant mi reflected the degree of rock soft and hard, the degree of disturbance to rock mass D and the rock uniaxial compressive strength ?ci. Finally, the influence rule of GSI to the rock masses angle of friction ? and cohesive strength c is analyzed. The result indicates that for the same GSI, the change scope is reducing for? while mi is changing from small to big and the cohesive strength tends to the identical value for different mi nearby GSI equal to 55.

Duncan-Chang model assumes the stress-strain relation of soils to be hyperbolical and presumes that the relationships between some parameters and ambient pressure are fixed, which not only goes against the fact of varied feature of soils but also can’t make the results of model agree with those of test perfectly. Based on analysis of test. with the development of computer, a lot of software is produced, which can fitting curves. So the parameters are able to be got by pilot calculation and the optimum functional relationships between some parameters and ambient pressure also are able to be hunted through these software. This method is different to that of Duncan-Chang model. On the basis of Duncan-Chang model, the negative-power model is established for soils; it’s able to display variety of the stress-strain curve of soils using a changeable parameter; and its parameters are determined in the previously mentioned way. The equation of tangent modulus is deduced based on the new method. The negative-power model can better meet test in comparison with Duncan-Chang model.

Numerical simulation with finite element method is adopted to analyze deformation and mechanical properties of layered salt rock. Firstly, with numerical experiment method, macro-equivalent elastic-mechanics parameters of layered salt rock with mudstone interlayers are predicted; and then a micro-finite element model of layered salt rock is established; micro-stress and strain distribution and stress concentration are studied under uniaxial and triaxial loadings. The above numerical simulation is compared with the corresponding experimental and theoretical study. The results show that the micro-finite element method, an effective method, can forecast the macro-mechanics properties of layered salt rock; the mechanical properties mismatch of two adjacent layers results in obvious stress concentration and differential deformation at the interlayer and interface; an equivalent tension stress is applied on the stiffer interlayer and correspondingly an equivalent compression stress is applied on the weaker salt rock under uniaxial loadings. While under triaxial compression, micro-stress and strain distribution of layered salt rock is complicated under different confining pressures and deviator stresses. The present study can intuitively analyze deformation and failure characteristics; it also provides a theoretical basis for further study of the stability of the oil/gas storage cavern in layered salt rock formation.

The correlation distance is one of the important parameters for the application of random field theory to reliability analyses. The traditional methods for estimating the correlation distance are studied and improved based on the random field theory. The fluctuation function method and weighted curve fitting method are presented which can make the calculation of correlation distance easier and get a more precise result. The vertical and horizontal correlation distances of typical stratum in Tianjin Port are analyzed in statistics based on a large amount of investigation data and the representative values of correlation distance of local area are obtained. Finally, the influence of sample spacing and soil index on the correlation distances is analyzed. The principle for determining the correlation distance with the varied sample spacings is presented. In addition, it is proved that the correlation distances estimated by different soil indices are similar because the correlation distance is the basic characteristic which is used to describe the variance of soil properties.

The prediction study of coal and gas outbursts is carried out by monitoring some indices which are sensitive to the initiation of coal and gas outbursts. The values and changing rules of the indices monitoring data are the foundations of coal and gas outbursts prediction. The principle of chaos prediction is firstly introduced; and then two group data of gas density are calculated using global model, zero order model and one order model. The calculation results indicate that the accuracy of weighted one order model is higher; and the selecting of prediction method is associated with chaos property of monitored data series.

The precise and immediate forecasting karst-fractured groundwater is a key problem to be studied and resolved currently in tunnel design and construction. Complex signal analysis can be used to extract multiple parameters to make a synthetical judgment. Based on this advantage, it is introduced to the prediction of water with the ground penetrating radar (GPR) to analyze the water response in the radar data from amplitude, frequency and phase, which overcomes disadvantage that the judge criteria is single, and provides a practical method to predict karst-fractured groundwater with GPR. The theory of complex signal analysis and necessity to be introduced to GPR signal processing is first illustrated. Then the feasibility of the karst-fractured groundwater prediction with GPR based on complex signal analysis is discussed; and the criteria to estimate water is obtained. At last, with project example, the GPR data is processed in complex signal analysis and the karst-fractured groundwater is analyzed. It is shown that the application of complex signal analysis improves the accuracy and credibility of prediction greatly in comparison with the excavation result.

To realize the harmony both mining and environment, early warning system of mining subsidence damage is presented and developed. Firstly, based on analysis of the damage early warning system, taking ARCGIS as the work window, adopting the development method of ARCMap Object, the mining subsidence early warning system is developed. Secondly, the displacement back analysis model of the calculating parameters of the system is presented. And the displacement back analysis program based on simplex method is developed. Thirdly, two cases are studied. In case 1, the subsidence damage due to a workface exploitation is analyzed. The resulsts are compared with those of CXYJ2001, and the system is proved to be not only reliable but also perfect functions. In case 2, the mining damage early warning analysis in Yaoqiao mine, Jiangsu Province is performed. According to the analysis, the exploitation design is optimized. Those studies show that the system is the important auxiliary method to realize the harmony both mining and environment. Lastly, the future study aims are introduced.

Rockburst is one of the main engineering geological problems greatly threatening the safety of construction. Prediction of rockburst is always an important project concerning the safety of workers and equipments in tunnels. The method of discriminant analysis is used to classify whether rockburst will happen in the underground rock projects and how much the intensity of rockburst is. Some main control factors of rockburst, such as the values of in-situ stresses σθ, uniaxial compressive strength σc and tensile strength σt of rock, the elastic energy index of rock Wet, are chosen in the analysis. Linear discriminant functions and criterion are obtained through training a large set of rockburst samples which come from a series of underground rock projects in domestic and abroad. Another samples are evaluated with the model. The evaluated results agree well with the practical records. Comparing the results of support vector machine method, fuzzy comprehensive evaluation method and artificial neural network method with discriminant analysis method, the evaluating results are same. Misjudgment ratio is low. Applying the classification model to rockburst prediction of the project of Kuocangshan Tunnel in Zhuyong Expressway, the result of classification is same as the results of fuzzy comprehensive evaluation method, artificial neural network method and numerical modeling method, just same as what happened in scene. It is shown that the classification model of discriminant analysis which with a low misjudgment ratio performed excellently with high prediction accuracy is an effective path to solve the problem of rockburst grade classification.