Based on fluid-solid coupling theory for discrete medium，containment and stability properties of underground crude oil storage caverns were assessed for the first pilot crude oil storage caverns in China. Elastic modulus and Poisson?s ratio were obtained in triaxial compression tests；while shear modulus and hydraulic aperture were obtained in shear-seepage coupling tests. The back analysis for the other parameters of surrounding rock was performed according to the deformation and water table change in rock mass around the service tunnel under construction. The containment property of the crude oil storage caverns subjected to the groundwater pressure of 50 kPa in the curtaining tunnels was assessed based on the laboratory tests and back analysis. It is obtained that the groundwater table would stabilize at 60 m above the crowns of the caverns，and more than storage media pressure inside hole. The crown settlements range from 9 to 30 mm，which satisfy the standard for the stability of the caverns. The distributions of horizontal stress，vertical stress，normal stress and shear stress around the caverns #8，#9 could be divided into three zones，i.e. excavation induced loose zone，disturbance and undisturbed zones. The extent of loose zone is about 6 m. The research provides theoretical basis for the design of curtain system of large-scale underground crude oil storage caverns.

The research area，in Lizhou district，Guanyuan City in the northwest Sichuan Basin，is located between the central faults and front faults of north section of Longmenshan fault belt. The major geological structural units in the research area are semi-platform unit and thrust nappe unit. The lithology is mainly mudstone and silt mudstone formed during the lower Silurian era，which are present almost all over the research area. In order to meet the requirements of one engineering establishment，the in-situ stress measurements by hydraulic fracturing method in four boreholes were accomplished；and the measurement time span was up to 23 years. The measured results indicated that：the in-situ stress state did not change in the past 23 years；the dominant orientation of the horizontal principal stresses in the research area was N24.4°W；and the stress gradients of the maximum and minimum horizontal principal stresses vs. depth were 0.036 and 0.025，respectively. The four feature parameters，kH max，kh min，?m and R，calculated through measured principal stresses，did not change during the 23 years. The research area is in the foot wall of the central faults of the Longmenshan fault belt，and is a passive wall. At the same time，the activities of fault movements and seismic events in the research area are extremely weak. Such a specific regional geodynamic conditions have determined the very stable stress field of this area. Comparing with the other research findings，the calculated ?m reflects the stress accumulative capability of the regional crust in this area，i.e. the magnitude of ?m reflects the strength of regional faults from the point of stress accumulation. Such a finding is consistent with the others′. In the future research，it is possible to use ?m values determined with the measured stresses and the corresponding data from the analysis of activities of fault movements and seismic events to evaluate the earthquake risk of one certain area.

Based on Froude similarity law，contrast model test on anti-explosion capacity of reinforced tunnels with local lengthening anchors in arch springing and equal length anchors is carried out. Mechanical and deformation characteristics and failure patterns of anchored tunnels are analyzed in the test. The research results indicate that，compared with equal length anchors，on one hand，under the extreme condition，when explosion center is very close to the tunnel，local lengthening anchors in arch springing have a closure effect on explosion load；and it can increase the explosion load on arch and the increment speed of relative displacement between vault and footwall. On the other hand，under the general condition，when explosion center is slightly far away from the tunnel，local lengthening anchors in arch springing can share or divert more explosion load；and consequently explosion pressure around tunnel，relative displacement between vault and footwall，the peak and residual values of compression strain at arch springing are decreased radically. Furthermore，the number of cracks in adjacent rock can be decreased and cracked degree are alleviated by preventing cracks from engendering and extending；namely it is propitious to enhance anti-explosion capacity of the tunnel.

The contract and frictional algorithms are developed in the meshless method，element-free Galerkin method for modelling 2D crack propagation in rock mass subjected to compressive and tensile loading conditions. Here，the level set method is used to describe the crack geometry. To capture the displacement jump across the joint when the join is open，the diffraction rule is used to modify the weight function；and hence construction of the discontinuous meshless approximation. The joint closure is modeled by a new meshless frictional sliding and contact algorithm，which is similar to the well known Goodman element in the family of finite elements to model the sliding and contact between joint surfaces. Different from Goodman element and former meshless methods，the construction of present method is based on the material points instead of the nodes，and thereby it performs better and is more flexible in model generation of a joint of complex geometry. The material points and nodes generation after joint propagation is based on the level sets functions which have a general form for arbitrary crack in 2D. A number of examples are tested to model the crack propagation in rock samples subjected to compression and tension showing the correctness of the method.

Currently，the dimensions of rock samples used in true triaxial experiment are either too large or too small，the span of dimension is large and magnitudes of stress levels are different，which brings inconvenience to the study of size effect of strength for rock mass in triaxial stressed conditions as well as its deformation and strength characteristics under complex stress path. To cope with this issue，the true triaxial experiment system for middle sized rock samples，named LWZ–10000，is developed. The design concept，composition feature，technical indexes and main function are introduced in detail. The system has such noticeable features as follows：(1) Automatic servo control and data collection during whole process of deformation failure with high precision and stable performance. (2) The dimension of rock samples is between that used in laboratory experiment and in field experiment. Moreover，the dimension can be altered in a certain range. (3) The magnitudes of lateral and axial loads can be large and the magnitudes are controlled independently in three loading directions. (4) Ultrasonic and acoustic emission experiments can be conducted simultaneously. A lot of true triaxial experiments for Jinping marble samples under different stress paths are carried out by the developed system. The whole process stress-strain curves and the relationships with wave speeds in true triaxial experiments under loading and unloading paths are analyzed. Combining with the true triaxial experiment results of different sized marbles under unloading path，the size effect of strength parameters for marble under unloading path is preliminarily studied. The successful development of this system provides new approach to studying the deformation and strength characteristics of deep rock mass considering multidirectional stress state and different stress paths.

It is important to realize the numerical simulation of the excavation blasting damage zone of high slope for the damage control of remaining rock. Based on the expression method of tensile damage by classical blasting damage models，the expression method of compression damage were introduced；and a modified method to determine the elastic physical parameters was put forward. Then，a new tensile-compression damage model was constructed. The established mathematical process of the model was derived in detail. The new model was programmed and linked to the computer code LS-DYNA through the user subroutine interface to realize calculation and test of the model. The damage effect in remaining rock of blasting excavation for Xiluodu down high slope of berm at elevation 640 m was simulated by the tensile-compression damage model. By the measurement of damage zone with acoustic detection，the effectiveness of the model was tested. At the same time，several common blasting damage models were used to make comparing calculation. The results show that the calculated values of the tensile-compression damage model agree well with the measurement of damage zone，and the proposed model?s accuracy is more precise than common blasting damage models.

Dynamic response characteristics and failure process of antidip layered rock slope under strong earthquake are studied by large-scale shaking table model test inputting sine wave in X-direction and XZ-direction. Testing results show that：(1) Acceleration amplification coefficients increase nonlinearly with the increase of slope height. The slope has the nonlinear height effect，i.e. more obvious of amplification more closing to slope top，and nonlinear surface effect，i.e. more intensity of amplification more closing to surface. (2) 3/4 of slope height is the critical height. Horizontal acceleration is amplified more obviously than vertical acceleration while above the height；but when below the height，the vertical acceleration is amplified more obviously. (3) The effect of frequency of seismic wave on the acceleration amplification coefficients is the largest. While the seismic frequency approaches to slope body?s natural frequency，the amplification effect is more obvious and the critical height is lower. (4) The amplitude of acceleration has no influence on distribution of its amplification coefficients in slope；but the larger the amplitude of acceleration is，the more the amplification coefficient is. (5) Failure process of the antidip layered rock slope under earthquake is divided into the following stages：earthquake induction；opening of structural surface at the top of slope；opening of structural surface at slope surface；increases of opening number of surface structural surfaces and depth of opening range，model blocks shearing broken at inner slope；rock structure loose at upper part and slope surface and arc transfixion crack along slope appearing. The zonal deformation phenomenon in the test has testified that distribution of acceleration coefficient in slope body is nonlinear.

Large consequent bedding rockslides widely exist in nature，which are one of the major types of landslides and have been the focus in landslide research area. Based on development morphology of sliding surface，consequent bedding rockslide is divided into two categories：advancing consequent bedding rockslide and regressive consequent bedding rockslide. It reveals from the mechanical point that the nature of progressive failure of consequent bedding rockslide is weakening process of mechanical parameters of landslide. It reflects in the constitutive equation of sliding zone is the reduction of the initial shear stiffness. Thus，ratio of the shear stiffness of weaken sliding zone to initial shear stiffness is defined as the weakening coefficient of sliding zone；and the S-shaped curve is introduced to depict the spatial characteristics of the weakening coefficient in sliding zone. Based on the characteristics of large consequent bedding rockslide，the progressive-locking mechanical model is proposed；and its mathematical expression is given. The model could well reflect the characteristics of the timeliness and spatial variability of mechanical parameters of sliding zone in the progressive failure process of the landslide. Finally，formulas and steps for calculating the stability of progressive failure landslide under this model are put forward. The model is applied to the case of Jiweishan landslide in Wulong county to analyze its stability before sliding.

Support selection is the key to application of advanced support technology with hydraulic support in gateways of coal face. Taking the selection of advanced hydraulic support in gob-side entry of working face 1302 in Xinjulong Mine as engineering background，the difference between the side strata structure of gob-side face and that of primary face is discussed；and the relationship between support and surrounding rock in gob-side entry of fully mechanized caving face is studied. Based on the moment equilibrium relations，mechanical model for determination of advance support strength in gob-side entry is established；and the viewpoint that strata rotary angle is the control object is proposed. Prediction of surrounding rock deformation of the gob-side entry is constructed by using displacement state equation of basic roof. Bearing capacities of coal pillar and solid side of the gob-side entry are calculated using the elastic mechanical theory. With the principle of squeeze nonoccurrence，the conclusions that the critical rotary angle of basic roof is 2.7°and the critical strength of advance support in the gob-side entry is 0.50 MPa are obtained. The advanced hydraulic support of ZTC30000/25/50 type is selected according to the results. Finally，the reasonableness of the support is verified by using observation result of surface displacement of the gob-side entry. The results can provide a reference for determination of reasonable strength of advanced support and support selection.

Based on the problems of the gateway of a mine of Huaibei mine area controlling surrounding rocks and different characters of tunnel surrounding rocks，management models and key technology were classified by coal seam types and whether driven along goaf or not that in premise of figuring out its feature and mastering failure reasons for supporting. Changes of deformations and stresses between before and after in two types of gateways is compared by numerical simulations during classification management. It was found that deformations of gateways surrounding rocks after classification management reduced greatly；and the stress levels of surrounding rock were significantly improved. Lastly，key technologies were applied to engineering practice. The practical result shows that deformations of gateways surrounding rocks were effectively controlled after classification management than those before classification management. The research results can be references for gateways surrounding rocks management under similar conditions.

Aiming at the controlling problem of the large deformations in the roof and coal sides in the process of surrounding rock support in large section coal roadways of deep mine，combining with the field investigation，numerical simulation，theoretical analysis，field test and field monitoring，the deformation failure characteristics of surrounding rock are analyzed. Then，a surrounding rock controlling system for large section roadway called double-cable-truss(DCT) is put forward. The composition structure，controlling mechanism and supporting superiority of DCT，stress field distribution characteristics of surrounding rock and key supporting parameters，etc. are researched systematically. The research results are as follows：(1) The deformation characteristics of large section coal roadways of deep mine are of large displacement，high sensitivity coefficient，continuous deformation and strong pertinence of failure. (2) Thick load bearing layer and rundle anchor structure in the surrounding rock of roadway are formed when using the new double-cable-truss controlling system. It could improve tensile and shear strength and ensure the surrounding rock and supporting structure to be stable. (3) The simulation results show that the vertical and uniform prestressed belts to the roof or two sides can be formed by the DCT. The stress dispersion degree is low and the effect range is 3–5 m. (4) A typical successful case of DCT application to large section coal roadway of deep mine is introduced in detail. The research achievements are applied to Xingdong mining area，which have great theoretical and practical values to similar roadway supports.

Multiplicity of solutions to inversion is a inherent problem of 3D electrical resistivity detection，which always causes errors and even mistakes in the geological interpretation. A research thought is presented to solve the problem，in which the structural and morphology information of anomalous body gained by other geophysical methods，e.g. seismic prospecting，ground penetrating radar，is used as prior constraints in resistivity inversion. First，construction method of a novel constraint named spatial structural constraint is proposed. The known anomalous regions obtained with other geophysical methods are mapped into 3D inversion model；and the difference between grids in corresponding regions is restricted to minimum. Thus，spatial structural constraint matrix is established to characterize typical geological structures，especially the more complicated structures；and it is relatively easy to be expressed mathematically and constructed. Based on above research，the objective function and inversion tomography equation of 3D resistivity inversion with spatial structural constraint are constructed. Then，numerical tests and engineering application are implemented；and the spatial structural constraint gained by ground penetrating radar(GPR) is applied to 3D resistivity inversion. It is found that the prior information increases greatly and false anomaly in inversion tomography is eliminated effectively. And the location precision and interface identification-effect are improved significantly compared with traditional method，making the inversion result be consistent with geological model or actual situation and the multiplicity of solutions be pressed obviously. And it is proved that the 3D resistivity inversion tomography with spatial structural constraint is a feasible way to reduce multiplicity of solutions and improve location precision and interface identification-effect.

Foundation pit excavation is constructed in intact soil strata. So，the stress path of soil is different from that in conventional retaining wall and in conventional triaxial compression test. In foundation pit engineering，in the soil in front of and behind retaining wall，the mean principal stress p or some principal stresses decrease in excavation，generally. As a result，the negative excess hydrostatic pressure in consolidated undrained(CU) triaxial test of saturated soil will conduct，that has effects on strength parameters of soil. It is pointed out that，for the excavation in clay soil，earth pressure calculation and stability analysis using strength parameters of CU triaxial test or consolidated quick shear test are unsafe under conditions of under-consolidation soil foundation and overcharge q which is applied recently. Meanwhile，in checkings of anti-sliding stability，anti-overturning stability and global stability by Swedish circle method for gravity cement-soil wall，if the strength parameters of saturated clay soil in CU triaxial test are adopted，the gravity of soil and wall in the calculation of resistant force has to be calculated by buoyant unit. According to the discussion on Technical specification for retaining and protection of building foundation excavations(JGJ120–201×)，the action of water pressure in calculation of excavation support structure is discussed；and it is proposed that for the silt soil foundation，whether the water pressure and earth pressure are estimated together or separately lies on the properties of the under soils.

The diversity of geological conditions determines the variety of the pit supporting engineering in Guangdong. Thus，different kinds of supporting patterns are used in Guangdong，which are rare in our country. Some new progresses and understandings are introduced in the paper，including the impact of precipitation on the surrounding environment and ways to deal with it，analysis of some different treatments with different results on the water in the bottom of pits and reasonable treatments，problems and countermeasures of the lateral displacement of piles generated by earthwork excavation in soft soil. Except that，some new and successful supporting types and the applications of the double-row piles method，top-down method and mid-island method are also discussed. Finally，the further study of some theoretical issues are proposed in the practice of pit supporting engineering，such as reasonable calculation of the force of prestressed anchor cable，the calculation mode of earth pressure，control of the pit displacement，reasonable supporting patterns in the deep soft soil and water and earth pressures in the residual soil. All these new and challenging scientific problems require further research.

By using numerical analysis，a series of parametric studies for the maximum wall deflection induced by excavation in clay are performed. Based on the results of parametric studies，a simplified evaluation method for maximum wall deflection is proposed using multiple regressions. The proposed method is verified through four case histories. Based on the comparison between predicted maximum wall deflections and those from field observation，the predicted maximum wall deflections are generally within 0.85–1.15 times of observed deflections. Therefore，the proposed method can be used for preliminary prediction and design，and also done for checking the final results of design.

Four selected engineering accident examples of composite soil nailing walls are particularly analyzed and studied；and some conclusions are drawn as follows. (1) When the safety factor of global stability checking of composite soil nailing wall meets the requirements of specification，the local stability can not be checked. (2) The “design bearing capacity” of nailing is difficult to be checked；and the“pull-out resistance of acceptance” could be adopted as the quality test standard and the basis of rod body strength design. (3) 6 kinds of composite soil nailing wall failure modes of the 13 kinds should be mainly checked and the other kinds could adopt structural measures，and so on. In addition，the research results include that：application conditions of composite soil nailing wall，methods of basic test and acceptance test of soil nailing，treatment principles of excavation of pit inside pit and edge-corner effect，exploration and survey requirements for surrounding environment，solution to bad engineering plan and coordination and lack of geotechnical engineering professional experience，etc. These theories research results have been reflected in the new implemented national standard of Technical Code for Composite Soil Nailing Wall in Retaining and Protection of Excavation.

The excavation-induced soil movements will adversely affect nearby buildings and bring additional deformation. Firstly，a three-dimensional displacement control finite element method(DCFEM) is proposed to analyze the influences of excavation of foundation pits on adjacent buildings；and the rationality of the method is proved by comparing with published centrifuge model tests. Then，the environment protection criterion for excavation，i.e. new revision Technical Code for Excavation Engineering is discussed；of which the disadvantage is shown by a case study. At last，a new deformation controlling criterion for excavation based on bearing capacity of adjacent buildings is obtained with calculation by DCFEM.

The shear force in retaining structure of foundation pits will be too large while the lowest support is set too high，which may lead to punching shear failure of the retaining structure. Such failure is a kind of brittle fracture and it usually occurs suddenly，which may result in disastrous consequences. The safety factor commonly used can only control the embedment depth of retaining structures，but they can not control the height of the lowest support. So，such failure can not be avoided. Therefore，the safety factor of the punching shear-resistant stability is proposed. The failure modes and features of punching shear failure of the retaining structure have been described. And then，the calculation method of the safety factor of the punching shear-resistant stability is put forward. The study results show that even all other safety factors are satisfied，it is still necessary to check the safety factor of the punching shear-resistant stability and to analyze the rationality of the lowest support height. The safety factor of the punching shear-resistant stability is applied to explain the failure mechanism of collapse accident of a domestic metro foundation pit. Calculation analysis also shows that using the safety factor to control the height of the lowest support can achieve a linear relationship between various safety factors and embedment ratio. The safety factor is simple in form and easy to calculate；so it has important applications to design and construction of the foundation pits.

The monitoring and theoretical studies for deep excavation are lack in Beijing. The monitoring results of deep excavation of China World Trade Center Tower phase 3 in Beijing during excavation process are analyzed. The study results show that：(1) Under normal circumstances，the displacement of pile-anchor bracing system is generally not more than 0.1%H，where H is the depth of foundation pit. (2) The stress of reinforcement in pile is usually only 1/10–1/8 of design strength. (3) The actual tension of anchor is smaller than the design value，which shows that the adopted earth pressure in the design of support system is larger than the actual earth pressure. (4) The tensions of each row soil nailings are all less than 38 kN，which is far less than the design value calculated by current regulations. It is found that the actual steel stress，anchor tension and soil-nailling tension are all less than the current theoretical values. The monitoring results can provide a reference to the similar projects and the basis for amendments to the subsequent procedures.

The foundation pits，as their complications in the respects of geotechnical engineering and particularities in the construction，can not be designed as the aboveground structures which are accomplished in one step. They should be designed in a dynamic manner and constructed in an informatization way on the basis of working conditions and monitoring informations in the process of foundation pit construction. Considering many aspects such as geotechnical parameters，calculation of water and soil pressures，calculation model of retaining structure，soft soil rheology and time-space effect，the complication of geotechnical engineering and the particularity of the foundation pit engineering are deeply analyzed；and the common reasons to several accidents arising from the foundation pit construction are anatomized. Meanwhile，several issues which should be concerned in the design，construction and monitoring of the foundation pit engineering are proposed.

The soft soil in the Pearl River Delta area has the features of high water content，high compressibility and low carrying capacity，etc.，which has put forward more stricter requirements for the design and construction of foundation pit project. Therefore，the supporting design under complicated environment for deep foundation pit on soft soil has become a new topic for geotechnical engineering. According to the particularities of the soft soil foundation pit，four key problems during the foundation design of soft soil foundation pit are discussed：(1) The force and deformation processes of the supporting structure are analyzed by the incremental method. (2) When considering the impact of the prestresses of the pit anchoring bolts and anchoring cables，the prestress leads the soil on the positive side of the foundation to suffer pressure. Therefore，the soil mass at the positive side shall be equivalent to earth spring. As for whether the earth spring has participated in the impact shall be judged by the displacement of the earth spring. (3) When the soft and weak earth foundation existing during the slope cutting，it is not only need to verify the overall stability of the foundation pit，but also need to verify the stability and carrying capacity of the earth foundation. (4) There are many issues about the forcing and deformation of double-row piles supporting structure needing to be studied further. With the specific engineering，the simplified calculation method of double-row piles is proposed. Many soft foundation engineering accidents have also illuminated that the foundation will have potential hazard risk if the above four key problems have not been thoroughly considered. Finally，based on the design of soft soil deep foundation pit，taking the solving method of the above four key problems as the theoretical support，the rationality is verified；and the common design scheme for adopting multi-supporting techniques for soft soil deep foundation pits are analyzed in detail，so as to provide some guidances for other similar projects.

In order to clarify the law of lateral deformation due to deep excavation in Beijing，a database of 37 case histories of field monitoring in Beijing is analyzed and the results are compared with worldwide case histories. Research shows that：(1) The maximum lateral deformation of wall mainly ranges from 5 to 25 mm，with percentage of 79.2%；and only 13.5% of that are larger than 30 mm. (2) The general profiles of lateral deformation of bored pile wall are “convex shape”. The distance of position of maximum lateral displacement is from 9 to 13 m below top of wall，and ranges from 0.58H+5 m to 0.58H－5 m. (3) The profiles of lateral deformation of compound soil nail wall are “triangle shape”，with the maximum value at the top of wall and decreasing gradually down. (4) The maximum lateral deformations of all excavations，which range from 0.04%H to 0.218%H，with a mean value of about 0.103%H，increase with the increase of H and length-width ratio. (5) The maximum lateral deformation decreases with the increase of insertion ratio and system stiffness，but it has little effect when insertion ratio is more than 0.6. The results can be used to predict lateral deformation of similar projects in Beijing and other areas，and guide design and constructions；and it also has great significance to preventing the foundation pit accident and avoiding the waste of resources.

Combined with engineering case of a super-large deep excavation constructed by frame-top-down method，the deformation and effect on around environments are studied. According to analysis of the monitoring data，some conclusions are drawn as follows. (1) The deformation of retaining piles could be controlled well by use of frame-top-down method；and the deformation law is basically consistent with that by normal construction method. (2) The ground settlements are smaller，but the effect range is far excess of 4.5 times of excavation deep，which is different from the predicted results by former experience. Dewatering is the main reason of wide effect range. (3) The non-uniform settlements of the adjacent building and underground pipeline are small；and their settlements are controlled in allowable range. The results show that the deformation of excavation can be controlled and the around environment can be protected effectively by using this method.

To analyze refreezing of frozen ground and its influence on foundation stability in the Qinghai-Tibet DC Transmission Line Engineering，temperature monitoring for a freezing-thawing process is carried out for the assembling prototype foundations and frozen soil in Wudaoliang area on the Tibetan Plateau. Combining with atmospheric temperature data in the area，the ground temperature changing characteristics with time and distributing along the depth of undisturbed and backfill coarse-grained frozen soil are analyzed. Monitoring results show that：(1) Ground temperature is periodic fluctuation and its amplitude decreases with increase of depth. There is a freeze-thaw state alternating layer in the upper undisturbed and backfill soil. (2) In the monitoring period，the frozen soil below foundation slab is in frozen state and the foundations are stable. (3) The maximum thawing depths of undisturbed and backfill frozen soil are 3.0 and 3.2 m respectively. Through the establishment of ground temperature estimation formula，and based on the results of ground temperature change amplitude and mean value，etc.，it is obtained that the permafrost table is 3.1 m，which is consistent with the results of engineering survey and monitoring. (4) Using heat transfer theories，ground heat transfer model of high porosity frozen soil backfilled in winter is established. The heat transfer ability and air natural convection velocity effects on refreezing of ground are analyzed. The results indicate that：(1) Backfill disturbance of frozen soil aggravates temperature fluctuation amplitude and increases the thawing depth，but the effect degree and range are limited. (2) Construction of transmission lines in frozen soil and assembly foundations in winter and keeping proper porosity of the backfill frozen soil in freeze-thaw active layer are beneficial not only to accelerate the ground refreezing，but also to increase compaction degree because of soil natural consolidation and thawing settlement. So，the frozen state in the warmer seasons could keep while heat diffusion to deeper ground weakens.