In view of failure phenomena with nonlinear large deformation including roof subsidence，sidewall bulge and floor heave occurred in mesozoic compound soft rock of Shajihai coal mine in Xinjiang，according to the methods of geological survey，theoretical analysis，numerical calculation，physicochemical test，hydrological properties test of soft rock，in-situ test，the composite failure mechanism of molecular expansion，movement of structural plane and excavation disturbance for mesozoic compound soft rock roadway in this area is analyzed deeply. Then，an initiative supporting technology system which is based on constant resistance with large deformation coupling support is proposed. Firstly，through constant resistance device，the swelling and plastic energy of surrounding rock is released fully；and the support load，stress concentration are reduced. With the aid of high-resistance performance，the excessive harmful deformation is restrained；and the plastic zone of surrounding rock is controlled reasonably. Secondly，uncoordinated deformation between the surrounding rock and support，which is caused by large plastic deformation and the dislocation of weak structural plane，is eliminated through the secondary bolt-net-cable coupling support. Grouting bolt is used to control large deformation of floor heave. Ultimately，a collaborative bearing system of the surrounding rock-supporting structure is formed. The optimizations of construction process and parameter design are studied based on the design method of nonlinear large deformation mechanics and numerical analysis. Engineering practice shows that this technology has been successfully applied to ensure the stability of roadway.

This paper presents the statistics and analysis of academic papers published by Chinese authors in recent 30 years in rock mechanics and geotechnical engineering journals published in Chinese and English. The statistics and analysis also include academic papers citations in the key databases such as EI and SCI. The paper tries to summarize and analyze the situation and development of rock mechanics and geotechnical engineering in China in the last 30 years，especially in the last 10 years. The developments are mainly focused on rock strength and deformation theories，rock fracture and damage mechanics，rock dynamics and constitutive relationships，rock nonlinearity and rock multifield coupling，rock reinforcement and stability analysis. Finally，ten challenging issues are proposed in the field of rock mechanics and rock engineering.

Compared with other filling materials，completely decomposed argillaceous sandstone shows some different engineering characteristics like low intensity，easy disintegration and softening after mixing with water. In order to guide the compaction control in field，the mineral components of soil are analyzed by X-ray diffraction test；and the accumulative deformation and slaking law under repeated loading and unloading conditions are studied by compression test and plate loading test. The study results are shown as follows: (1) The compression curves of completely decomposed argillaceous sandstone are of concave type in compression test or convex type in plate loading test；and all rebound curves are of concave type. (2) The (i+1)-th compression-rebound curve is located below the i-th curve，and they have the similar linearity. (3) The more the number of equivalent loading compression，the less the settlement increment，but the more the accumulative settlement. Soil residual deformation tends to be stable after 3 times of compaction. (4) The over-loading compression curve will be back to extension line of the first compression curve，and has memory effect. (5) The larger the repeated load，the larger the single total and permanent deformations. (6) After the repeated loading and unloading，the compacted soils become slaking with water，and produce the slaking settlement. (7) The compression curves of slaking soils are of concave type；and the higher the over-load，the less the deformation under the same pressure. In the practical process of construction，it is better to increase the tonnage of the road roller than to increase the number of compaction operations.

Fractures initiated from free surface of layered rocks，which are called surface cracks，often terminate at the interface which divides the fractured layer and the matrix layer，but can continue to propagate along the interface. A numerical simulation is carried out to study the mechanism of surface fracturing process including micro-fracture formation，propagation，coalescence，nucleation，fracture infilling，fracture saturation，termination，and interface delamination. A model with a fractured surface subjected to uniaxial tension is simulated firstly. It is found that the stress distribution between fractures depends on the fracture spacing；and the stress distribution will directly affect the fracture mode. New fractures can either appear in the surface layer(parallel to existing fractures)，or appear between the layers(interface peeling). Furthermore，an existing fracture can propagate to the underlying layer with no fracture inserting(fracture saturation). Secondly，material homogeneity is considered in the simulation；and the results show that the stress distributions in homogeneous and heterogeneous models are different. A smaller stress is required to produce the same fracture spacing in the heterogeneous model；and the critical values of the spacing to layer thickness ratio at fracture saturation are almost the same. Lastly，stresses in a few sections during fracture formation are analyzed；and it is found that stress transformation can be used to explain the mechanism of fracture saturation. A fitting curve of the relationship between strain and spacing to layer thickness ratio is obtained. It is found that fracture spacing in the case of interface delamination is greater than that without interface delamination. Stress transition between the two layers on fracture spacing in the fracture process is also investigated，with a focus on stress transfer mode.

Based on the theory of elastic wave and the summarized geological model，a new time-frequency analysis method of the rock slope seismic stability is put forward by using the Hilbert-Huang transform. The rationality of this method has been verified by the results of shaking table test and numerical simulation. This method not only considers the amplitude-time-frequency effects，but also can forecast the safety of the slope，the time occurring the landslide and its scale. At the same time，this method can provide the valuable references for the time-history seismic design of retaining structure in the high intensity earthquake area.

Mathematical expression of vibration deterioration effect of structural plane is obtained by experiments；and then the expression is applied to rock slope?s dynamic stability analysis. 3DEC is selected as calculation engine，and at each dynamic calculation step，mechanical parameters of structural plane are refreshed according to the real-time values of dynamic response；meanwhile，the earthquake inertial force at that moment is obtained via net vectorial nodal force?s vector calculating. Hence the rock slope?s instantaneous safety factor is obtained based on the limit equilibrium theory. Therefore，the time series of factor of safety can be got for whole earthquake process by dynamic calculating；and the dynamic stability evaluation index is determined by minimum average safety factor method. Consequently a new method for analyzing dynamic stability of rock slope is presented，which takes vibration deterioration of structural plane into account. Finally，the method is used to study a rock slope case in Wenchuan earthquake-affected region；and the analytical results matched actual geological survey situation well，so as to testify the feasibility and correctness of the proposed method.

The conventional particle swarm optimization is improved by composing a nonlinear inertia weight function and importing in an acceleration factor，which can enhance the convergence and efficiency of computation. At the same time，the improved particle swarm optimization is improved again by message passing interface(MPI)-based master-slave parallel framework. The back analysis process of large-scale underground engineering which based on the ordinary computer fleet system distributed-storage parallel mode is compiled with Fortran language. According to distributed-memory parallel mode，the parallel computation can be conducted and completed using computer cluster networks；thus considerably reduce the cost and enhance the efficiency of computation. The results indicate that the improved particle swarm optimization is efficient. Moreover，the influences of excavation damage of surrounding rock mass，reliability of measured data，parallel granularity and load balance on computational efficiency and accuracy of back analysis in underground engineering are briefly discussed. The proposed improved method and the rational recommendations provide the back analysis of parameters and dynamic optimal design of underground engineering with a new idea.

In the prevention and control of water hazards in mines，grouting curtain is widely used as a useful method to prevent water seepage. With the increases in mining depth and the service life of curtain，the capability of curtain to prevent water is reduced. Taking curtain repairing project of Zhangmatun iron mine for example，the hydrogeology analysis，dewatering test，transient electromagnetic exploration and connection test were carried out to find the weak zones of the curtain. A comprehensive analysis method to find the weak zones of the curtain was proposed. The range of grouting treatment was determined；and reasonable borehole design and grouting scheme were proposed，which bring in a good treatment effect. Practice shows that this method can provide certain reference for similar projects.

Based on field measured data，the lateral deformation laws of retaining wall，which belongs to super-large deep foundation pit of Shanghai Tower podium，are analyzed. The analytical results show that，during the period from completion of cushion concrete placement to the completion of beam-slab concrete placement，the increment in lateral deformation of retaining wall is very small，indicating that the constraint effect of cushion on deformation of retaining wall is significant. However，due to the eccentric load effect，the lateral deformation of circle wall，which is the support point of cushion，is relatively large；and it leads to a large increment in lateral deformation of measuring point P04 during this period. Combining with the site construction conditions，the constraint effect of cushion concrete is explained. During the period of structure concrete curing，due to the concrete shrinkage of overlong beam-slab structure or bottom plate，the increment in lateral displacement of retaining wall is large. During the curing period of bottom plate，the increment in lateral deformation of measuring point P23 is larger than that caused by soil excavation for the last time. For the short concrete structure，the effect of concrete shrinkage on the lateral displacement of retaining wall can be neglected. Finally，based on the above laws，some suggestions are proposed to control the deformation of retaining wall effectively.

The static and quasi-dynamic tests on granite specimens under various strain rates are conducted by using rock dynamic loading system. The specimens are 50 mm in diameter，with the length of 50，75，100，125 mm，respectively. The research results are drawn as follows：(1) Specimen strength is significantly dependent on strain rates and increases with the growth of strain rates with a power relationship. (2) Under static and quasi-dynamic loading conditions，rock strength generally decreases with the increase in specimen length. (3) When the diameter of specimen is 50 mm，the aspect ratio should be not smaller than 2；then steady test results can be obtained under different strain rates. (4) Peak strain under each strain rate decreases with increasing specimen size. (5) Both of secant modulus E50 and elastic modulus Et increase with increasing specimen size；and Et is larger than E50. (6) Failure mode is significantly dependent on strain rates and failure is serious when the strain rate increases. When strain rate  ＜10－3 s－1，failure mode has a process of split failure-taper failure-shear failure；when strain rate  ＞10－2 s－1，the failure mode changes from taper failure to shear failure directly.

In order to find a reasonable construction scheme system for tunneling in crushing phyllite，the field tests and numerical simulations are combined to present the variation laws of the deformations around the tunnel，axis forces of anchors，contact pressures between surrounding rocks and primary support as well as between primary support and secondary lining，and the internal forces in arch frames and the secondary lining under 7 tunneling schemes. The study indicates that the schemes S1 and S2 are both unsuitable for the tunnel excavation because of the large deformation and other hazards. The excavation conditions are satisfied in scheme S3，but the supporting system should be reinforced. For schemes S4–S7，the deformations will be controlled effectively to maintain the tunnel stability. However，in addition to the heavy loads applied on the supporting system，the schemes S5 and S6 will result in numerous construction difficulties，long construction period and high cost. For scheme S7，the surrounding rocks are most frequently disturbed and the primary lining cannot be enclosed in time. For scheme S4，the deformations of the surrounding rocks can be well controlled，whilst the loads can be reduced and the supporting pressure can be provided for tunnel stability. Besides，scheme S4 can be transformed rapidly to schemes S6 and S7. It is beneficial to maintain the long-period stability of tunnels excavated in crushing phyllite or other soft rock layers.

With the rapid development of Chinese hydropower construction，more and more large-scale projects encounter the stability problems of dynamo-relaxed rock mass. The deformation characteristics and failure mechanism of dynamo-relaxed rock mass are very complex. Based on the monitoring data and geology data of the tension-displaced rock mass on right bank at head area of Pubugou hydropower station，analysis method of the displacement characteristics and failure mechanism using monitoring data has been summarized. In addition，the comparative analyses of deformation characteristics are made to verify the method among the tension-displaced rock mass of Pubugou，the Geheyan Maoping landslide on Qingjiang River and the upstream slope of Pubugou rockfill dam. The results show that：(1) The tension-displaced rock mass moves in the way of blocks dislocation；and the slope terrain controls the direction of dislocation. (2) The failure mode of the tension-displaced rock mass is in the partially gradual way；and suddenly global failure can hardly happen. Nowadays，there are major differences in dislocation direction，dislocation time of rock mass at different locations. (3) Using the monitoring data from vertical inclinometer hole，dislocation zones are divided into two categories (I and II)，and the class I is further divided into two sub-categories(I1 and I2). (4) The deep support using anchor cable should emphasize the identification of the type of dislocation zone and should especially control the Class I dislocation zone，and should emphasize the support of random bolting. (5) The tension-displaced rock mass is not sensitive to rainfall and to change in reservoir levels.

Engineering practices and model test results all indicate that overburden soil stratum is often able to withstand greater head pressure than the pressure of its own weight. Currently，no relevant theory can explain this phenomenon. The concepts such as generalized buoyancy，generalized buoyant unit weight and generalized hydraulic gradient are proposed by considering adsorptivity of soil particles to pore water as well as considering connectivity of bound water；and then specific calculation method is given，explaining the physical meaning of the parameters such as  ，  and   used in the calculation and recommending the estimating method of  . The tests envisaged on measuring  and   are also given，then the relationship between  and initial hydraulic gradient   is established. Aforesaid calculation method takes the different natures of soil into account. For sand and loose soil，generalized buoyancy，generalized buoyant unit weight and generalized hydraulic gradient are changed into Archimedes buoyancy，traditional buoyant unit weight and hydraulic gradient. Further，calculation method of seepage force in different soils has been given. In the end，the unified expression of failure conditions of soil under the action of groundwater is got，which can interpret several different failure modes of soil under the action of groundwater. According to this theory，the calculating method of anti-seepage stability and the stability of resistance to the confined water of foundation pits should be amended and the current calculation method can only be applied to sand and loose soil. Some conclusions derived by using this calculation method to analyze the stability of soil in groundwater under different strata combinations are different from traditional arguments. For example，when analyzing the embedment depth of enclosure structures，if there is no impact of confined water，the seepage failure of the foundation pit is difficult to occur in the clay stratum and the ability of foundation pits to resist seepage failure in the silt stratum is better than that in sand layer. When analyzing the anti-upbursting of confined water in foundation pit，the traditional ballast-balance calculation is unsafe to the overburden soil stratum with permeability，while for the overburden soil stratum of confined water stratum containing a certain amount of silt，its ability to resist the confined water pressure is relatively increased. Finally，based on the result of the paper，the unified calculation theory on soil-water pressure is amended.

It is difficult to choose an appropriate calculation method to determine the effective enclosure system in foundation pits design. This case study deals with the excavation of Jiangbei shield working shaft of Weisan road over-river tunnel in Nanjing，which is a typical deep working pit in soft soil strata. The spatial foundation plate method was used to analyze the deformation and stress condition of the structure of the shield working pit under dewatering outside the foundation pits. The m values of strata are obtained through back analysis；and the active and passive areas were judged by the DLOAD subroutine. The calculation results are consistent with the measured results；so the spatial foundation plate method with m values from back analysis can effectively predict the deformation and stress behavior of the enclosure structure. In order to further optimize the structure，three factors，i.e. thickness of diaphragm wall，size of supporting section and m value of soils within 5 m below the floor，are selected for orthogonal array experiment；and the main influencing factors of horizontal displacement of diaphragm wall and axial forces of bracings are obtained. The calculation method and the relevant results can provide references for similar engineering.

Cyclic triaxial tests were performed on marine sandy soil from Zhoushan Seas by GDS loading apparatus under different exciting amplitudes of bidirectional wave loadings to study the liquefaction of typical marine soil samples MS1 and MS2，which are taken from Wushitang coast and Dongsha coast respectively. X-ray diffraction(XRD) and scanning electron microscope(SEM) experiments were accomplished to study the phase structures of MS1 and MS2. MS1 and MS2 are both alkaline marine sediments with quartz mineralography. It is found that the high-cycle liquefaction on marine coarse sand MS1 can be induced under low amplitude and its low-cycle liquefaction can be induced under high amplitude. The marine fine sand MS2 can carry high-cycle wave loading under low liquefying deviatoric stress and can carry only low-cycle wave loading under high liquefying deviatoric stress. The liquefaction pore pressure model and its controlling parameters? values are established based on the normalized relationship between cycle-time at any time during initial liquefying period and initial- liquefaction critical cycle-time. The typical marine sandy samples MS1 and MS2 are inclined to be liquefied under the accumulation of exciting stress ratio. The endochronic failure model under initial-liquefaction and its controlling parameters? values are obtained based on dynamically incremental pore-pressure ratio and damage parameter introduced by Finn. It is found that the liquefying failure of MS1 is induced by shear-contraction due to excessively exciting compression strain；and marine fine sand MS2 is liquefied under cumulative tension strain that causes the contacts failure of soil particles. The cumulative deterioration for micro-meso-physical structures of marine sediments induces their macro initial-liquefaction failure. The macro-mechanical characteristics of marine sandy soil from Zhoushan Seas consist with their micro-meso-physical phase structures evolution.

Centrifugal model tests were designed to simulate hydraulic heave in low permeable cohesive soil under the action of confined water. The bending moment，horizontal displacement and stability of retaining wall at different excavation depths and confined water levels were analyzed. In addition，the heave deformation and hydraulic failure at excavation bottom were observed. Test results indicate that：excavation bottom uplift and deformation curvature increase with increases of confined water pressure and excavation depth；and cohesive soil progressive fracture appears in the center of foundation pit. At passive side of retaining wall，the resistance of soil gradually decreases；while the bending moment and horizontal displacement of retaining wall become greater. Eventually，vertical crack appears in the soil behind retaining wall；and test foundation pit collapses because of hydraulic heave. When analyzing hydraulic heave stability of foundation pit considering the shear strength of cohesive soil，cohesion c should be multiplied by a reduction factor to take some adverse factors into account，such as interface defect of soil-retaining structure，progressive hydraulic fracture and cohesive soil softening induced by groundwater，etc..

The anti-slide pile is simplified into a two-dimensional model and is designed with the calculation width Bp in the conventional anti-slide pile design method in China. The improved method is studied for the unreasonable simplification of the frictional resistance beside the pile. The shear constitutive equation of the cementation surface is obtained by the concrete-rock cementation surface shear test. The equation is applied to the design of socketed segment of anti-slide pile；and then the design formula based on K method is derived. By using Majiagou #1 landslide  as a case to make comparison between the aforementioned improved method and conventional K method，it is found that the difference of pile displacement is great and the difference of internal force is neglectable. Through sensitivity analysis，it is concluded that the pile displacement reduces with the increasing residual shear strength f and the decreasing critical displacement xs. The influence of f on pile displacement is greater than that of xs；both of f and xs have slight effect on internal force distribution. Displacement is an important index in anti-slide pile design；so the anti-slide pile design should take the distribution of frictional resistance beside the pile into account and combine with the cementation surface shear test.

A simplified approach for nonlinear analysis of the load-displacement response of a single pile and pile groups embedded in multilayered soils is presented. Two models are adopted in the proposed method. One model uses a softening nonlinear relationship to simulate the degradation behavior between pile-soil relative displacement and unit skin friction developed along the pile-soil interface；and the other model adopts a bilinear displacement-unit end resistance relationship to capture pile end response. A highly effective iterative computer program is developed to analyze a single pile response using the proposed two models. Furthermore，based on the settlement of a single pile derived from the proposed computer program and the equivalent pier method，a simplified calculation approach for average settlement of pile groups is presented. Comparisons of the load-settlement responses demonstrate that the proposed method is generally in good agreement with the field-observed behavior and the calculated results derived from other approaches.

Dredged fill behaves some characteristics of high water content，high compressibility and low permeability，due to the difference of formation conditions and stress history. Dredged fill behaves different permeability characteristics from natural soft clays，and it is very difficult to determine its permeability coefficient by conventional permeability test apparatus. The disadvantage of existing permeability test apparatus is overcome by GDS consolidation test apparatus，which has some great advantages for the study of nonlinear permeability characteristics and determining permeability parameter of dredged fill. Consolidation and permeability tests are performed on dredged fill in the Qianwan area of Shenzhen city by GDS consolidation test apparatus. Regression fitting analysis of four common nonlinear function relationships of permeability coefficient-void ratio for soft clays are performed；and some fitting parameters are also obtained. The obtained results indicate that：(1) After a certain consolidation pressure between 6 and 400 kPa，with the increase in consolidation pressure，a nonlinear variation in permeability coefficient of dredged fill is shown，the reduction of which is 1–2 orders of magnitude. (2) Four common nonlinear function relationships of permeability coefficient-void ratio for soft clays are conformable with dredged fill in the Qianwan area of Shenzhen city. Because of the characteristics by a simple form and best fitting，the power function relationship of permeability coefficient-void ratio is considered as a preferred nonlinear permeability relationship in the numerical analysis of large-strain and nonlinear consolidation behaviors of ultra-soft soil such as dredged fill.

Combined anchoring technique of tiebacks and soil nails is frequently used in practice for stability of granitoid soil slopes due to their higher anchorage capacity. Despite the routine use，the existing design method for the combination remains however controversial，in which the soil nails are designed to enhance local stability rather than contribute to overall stability of the slopes. The tiebacks are always designed to balance the driving force of a slope. Thus，the current design method cannot reflect the advantages of the combination. Attempting to solve the problem，a new design method is presented，in which the contribution of the soil nails，as well as the tiebacks，to overall stability of a slope is taken into consideration. As a result of this consideration，the preload of the tiebacks decreases and the slope consequently moves(the quantity of the movement is very small) and the movement mobilizes the resistance force of soil nails. By this process，the passive and active anchors work harmoniously；and the stress corrosion possibility of the active anchors(tiebacks) is reduced due to the decreasing of the preload resulting in a better long-term stability. Also，the amount of the tiebacks may decrease，which can save the construction cost. A granitoid soil slope along G323 national highway in China is taken for example to validate the presented design method by the field investigations of preload in some tiebacks，the stress in some soil nails and the ground surface displacement.

In order to reveal the mesoscopic deformation mechanism of loess high-fill foundation of Luliang airport，the soil electrical resistivity-consolidation combination measuring instrument are developed based on the principle of soil electrical resistivity. The dynamic variation law of the electrical resistivity of Q3 loess are obtained through in-situ monitoring，field sampling and laboratory test under different initial saturations and constant load. The electrical resistivity-strain curve model of Q3 loess to the limits of optimum moisture content is proposed；and its moisture migration and structural changing characteristics under constant load are also obtained. The study results show that the post-construction deformation of the loess high-fill foundation top surface is composed of the consolidation deformation of initial foundation and the fill bellow the surface to a certain depth and the long-term creep deformation of deep overconsolidated soil. The mesoscopic deformation mechanism of soil is revealed initially；and the study provides scientific basis for the establishment of loess high-fill soil constitutive model and reasonable selection of the numerical analysis model.