It is important to conduct a research on the stress state of the rock masses in the upper earth′s crust. In-situ rock stress measurement is the basic and reliable access to obtain the stress state of the rock masses. The development of in-situ rock stress measurement and state-of-art of research on it are overviewed. Then，several in- situ rock stress measuring methods and techniques are briefly analyzed in rock mechanics and engineering. A new method，borehole wall stress relief method(BWSRM) to determine the in-situ 3D rock stress tensor in a single drilled borehole is deliberated. An original geostress measuring instrument typed by BWSRM-H01 is designed and manufactured based on the principle of in-situ rock stress measurement with BWSRM. The in-situ test for rock stress with BWSRM is carried out at an experimental tunnel in Jinping II hydropower station，China，where the buried depth of overburden is about 2 430 m. It is shown that the two principal stress components close to the horizontal direction are the maximum and intermediate principal stress respectively；while the stress component close to vertical direction is just the minor principal stress in the testing site. The magnitudes of the maximum and the intermediate principal stress are high；and both of them are very close.

The problem of freezing-thawing damage of rock mass involves thermo-hydro-mechanical(THM) coupling at low temperature. Based on the phase transition theory and the energy conservation principle，the expression of frozen ratio is derived. Using the dual-porosity medium theory，the governing equations of THM coupling of freezing rock are obtained according to the law of mass conservation，the law of energy conservation and the principle of static equilibrium. Finally，considering the influence of freezing process on permeability，an example of fractured tunnel is given to reveal the distribution of temperature field，stress field and pore pressure under THM coupling condition by using the method of equivalent thermal expansion coefficient.

Elevation amplification effect of blasting vibration is an important study content of vibration propagation law on rock slope. Based on the theoretical analysis of elevation response mechanism on rock slope，numerical simulation of blasting vibration induced by slope excavation and measured data analysis，the blasting vibration elevation amplification effect has been studied. The results indicate that the blasting vibration elevation amplification effect occurs under some conditions and it is affected by factors such as the property of blasting vibration and the slope form. Under the blasting load，when the natural frequencies of different slope benches correspond with the main frequency band of blast load，the“whiplash effects” are caused in rock structures of the slope benches and the vibrations are amplified. While slope form changes rapidly and slope gradient increase，the vibration velocity of higher slope bench may be larger than that of lower slope bench，which generates significant elevation amplification effect of vibration. Under the similar slope form，the vibration velocity at the toe of slope bench decreases with the increase of the elevation and the elevation amplification effect of vibration is not caused. Under the“whiplash effect”，the vibration velocity at the edge of the slope bench is bigger than that at the toe of slope bench on the same elevation；but the stress and strain are smaller. So the vibration velocities at the edge of the slope bench are not appropriate for evaluating the stability of rock slope.

Based on the monitoring data of the Kuyu diversion tunnel，the deformation characteristics and mechanisms of the water-rich soft rock tunnel are analyzed. The results indicate that the convergence deformation of sidewalls and the subsidence of the vault develop towards constant values，the former takes much more days，and the value of the sidewalls deformation is 2–3 times as much as that of the vault. The deformation of soil tunnel is influenced by the combined tempo-spatial effects. And the ratio of deformation produced by the time-effect is quite large even in the range impacted by excavation. The effect distance of space-effect on sidewalls deformation is in range of 4D–5D. And comparing with the deformation of vault，the time-effect of the sidewalls deformation is more remarkable. The differences between the sidewalls and vault deformation characteristics are mainly determined by the types of rock deformation and the way of stress release. The time-effect of stress release of surrounding rock around the sidewall is obvious. The plastic area and deformation pressure increase with time and take a long time to reach stability. In a certain depth，the rock mass at the vault has an integral settlement deformation together；and the rock pressure can reach stability quickly. The research results can provide some scientific guidelines and valuable references for construction and monitoring of soft rock tunnel projects.

The problems including support design，construction control and overall stability of surrounding rock are very serious in the underground caverns of Jinping I hydropower station. The unloading deformation and failure characteristics of surrounding rock under the conditions of high stress and low strength stress ratio have been clearly shown during the excavation. According to the mechanical characteristics of layered rock，the initial stress field and mechanical parameters of layered rock are obtained by inversion analysis considering the unloading mechanical evolution of layered rock and its numerical simulation method. Based on these，the three- dimensional numerical simulation for the underground caverns of Jinping I hydropower station is carried out；and some opinions of surrounding rock stability and support safety under high stress are obtained. The right engineering control suggestions including stress release control，capacity control of damaged zones and deformation cracking control，and so on，are put forward. The results show that the rationality of raised opinions and proposed control measures are confirmed by in-situ monitoring results of underground caverns and stability status of surrounding rock. It is shown that the proposed layered rock constitutive model and its numerical simulation method can reflect favorably the working behaviors of layered rock mass in the construction of large underground caverns in condition of high stress.

Referring to the numerical manifold method，the dynamic finite element method with fixed meshes for the excavation simulation of complex slope is presented. By using the new method，only the discontinuous surface and complex terrain should be taken into account but not the explicit excavated elements. The location of excavated surface is just considered as an inputted real-time dynamic parameter. So，the time-consuming of the preprocess can be significantly deduced. The domain is divided into two parts：the reserved domain and excavation domain，which are determined with the help of geometric topology. By using the intensive Gauss numerical integration method，the total stiffness from the reserved domain and total load vector from the excavation domain are assembled with the displacement interpolation model of normal finite element method. Based on the principle above，the calculating procedure is programmed. The excavation simulation of Kongquegou slope of Xiaowan arch dam is studied by the new procedure. The results are in accordance with those from the general finite element method. The precision and validity of the new method are proved. The biggest advantage of the method is that the preprocessing is very simple；and it can be used in the excavation simulation and shape optimization for complicated slopes and caverns.

Aiming the limit of traditional transient electromagnetic method(TEM) detection in tunnels only depending mainly on 2D apparent resistivity，a method of transient electromagnetic multipoint array detection in tunnels is presented learning from the fixed-loop survey method when detecting on the ground. The calculation method of high oscillation dual Bessel integration in frequency domain TEM response of non-central vertical component is studied. Taking the polynomial of center component in frequency domain as a basis function，a polynomial of non-central vertical component in frequency domain is defined；and the polynomial coefficients are obtained by least square fitting. The formula of non-central vertical component in time domain is derived. The late-time apparent resistivity of non-central vertical component is also derived according to the late-time approximate conditions of transient electromagnetic field. Transform of non-central vertical component of TEM detection in tunnels into apparent resistivity image is realized. It is the basic theory for transient electromagnetic multipoint array detection method in tunnel. The interpretation method using three-dimensional(3D) apparent resistivity images combining the multipoint response is also proposed. On the basis of the theory studies，transient electromagnetic multipoint array detection method is studied combining the field test in one tunnel. The transient electromagnetic multipoint array detection method for water bearing structure under the tunnel floor are carried out；and the comparison and interpretation are also given about the detection results. A 3D apparent resistivity image is formed；and the 3D space distribution law is obtained by analyzing the 3D apparent resistivity image.

In the process of hot dry rock(HDR) geothermal energy development，the first issue to be resolved is deep drilling. According to the geological characteristics of HDR geothermal resources in China，the three key issues during HDR geothermal drilling construction are proposed based on the experimental research，theoretical analysis and numerical simulation. They are drilling surrounding rock stability control technology，rock breaking technology under high temperature and high pressure and drilling fluid technology under high temperature and high pressure. And then，from the main factors of surrounding rock instability in exploitation of HDR geothermal energy，rheological properties of drilling surrounding rock under thermo-mechanical coupling，drilling surrounding rock deformation failure law and the critical failure condition under high temperature and high pressure，the drilling surrounding rock stability control technology during the HDR geothermal deep drilling is proposed. Through the experimental research on rock breaking in granite with three methods which are impact grinding rock breaking，cutting rock breaking，impact-cutting compound breaking rock under high temperature and high pressure and the comparison of the three rock breaking methods under different temperatures，the rock breaking laws of the three methods are obtained under high temperature and high pressure. Finally，from the effect of high temperature on drilling fluid，the general requirement of high temperature treatment for geothermal drilling and the effect of the performance of drilling fluid on wall stability and its countermeasures，the drilling fluid technology requirements of HDR deep drilling are solved. The research on deep drilling technology under high pressure and temperature has important scientific and engineering significance to the human exploration of Earth and the development of deep earth energy and resources.

Three groups of conventional triaxial tests，square triaxial tests and plane strain tests of rockfill material are conducted to study its strength in plan strain stress state. Significant differences between conventional triaxial tests and square triaxial tests show that peak strength of latter is higher than the that of former. Especially when its density is large，the stress-strain curve shows softening characteristics and obvious peak deviatoric stress. Each Mohr circle of square triaxial tests has a common tangent，and so do plane strain tests. Thus，Mohr-Coulomb strength criterion is reasonable to reflect its strength characteristics. Lode parameter of same kind of rockfill material approximately keeps constant in its failure state and their values are close to the sine internal friction angle of square triaxial tests. Based on experiment results，the relationship between strength parameters of rockfill material in plane strain state and square triaxial tests is established using the unified strength theory. Through the analysis of influence parameter in plane strain state，it is shown that the internal friction angle of plane strain state is only related with the friction angle of triaxial state；and its cohesion mainly depends on the corresponding parameter of triaxial state and the friction effect is minor. Finally，the results of theoretical formula are compared with test results. It is shown that the formula of strength parameter proposed in this paper can mainly describe the strength characteristic of rockfill material in plane strain test under constant minor principal stress.

According to borehole cores with the length more than 1 500 m in deep tunnels at Jinping II hydropower station，the information of the macro-damaged characteristics，quantity and thickness distribution of discing core were collected and the spatial distribution of core discing was analyzed. Then，the influences of different buried depths，geologic structure，tunnel geometric size，drilling diameter and directions on core discing were studied in combination with the results of elastic wave test and digital borehole images. Simultaneously，by applying scanning electron microscope technique for discs? surface，the micro-damage mechanism was discussed. The results indicated that：(1) The relationship between the quantity and thickness distribution was similar to a power function form. The quantity of core discing increased with depth and tunnel dimension. Within the zone of 3 times of tunnel diameter，core discing occurred more frequently. (2) The convex-concave formation was related to stress distribution，internal damage and mineral structure types. (3) Core discing often occurred under the joint action of geological and external effects. The native micro defects，structural plane and external disturbance were the discing foundation；the local stress concentration and stress release were the power of discing；the continuous drilling was the intrinsic cause of core broken into pies；the radial cut-compressive，axial tensile stress and lateral expansion of rock cores were the mechanical response of rock mass fracture. (4) Discing zone characteristics were the comprehensive reflection of rock damage weakening，rock mass structure and local stress concentration.

According to the nonlinear failure characteristic of rock mass，a new calculation method for critical slip field of slope is proposed based on generalized Hoek-Brown failure criterion. The Hoek-Brown failure criterion based on the geology strength index(GSI ) is one of the most useful criteria for forecasting and computing rock mass strength. Firstly，the parameters of rock mass strength are obtained by Hoek-Brown failure criterion. Secondly，the shear strength of each point on the Hoek-Brown strength envelope is transferred equivalently to the Mohr-Coulomb linear relation which is tangent to the nonlinear envelope with relevant cohesive and frictional parameters. Finally，the new iterative method is established and the critical slip field of slope by Morgenster-Price method is improved. And then，the most dangerous sliding surfaces are traced according to the principle of maximum thrusts with satisfying both force and moment equilibriums；and the corresponding safety factors are calculated quickly and exactly. This method is applied to the stability analysis of two slope examples and one case slope. The results show that this method absorbs the advantages of critical slip field and Hoek-Brown failure criterion and can consider the nonlinear failure characteristic of slope. The calculation result is more closer to the practical situation.

The loose deposit landslide was significantly influenced by the groundwater level which was easily monitored and changed before the slope surface moving. Based on the relationship between surface displacement and groundwater level，taking the monitoring of the groundwater level as landslide prediction or aided prediction had a broad prospect. The vector auto-regression model could be applied to analyze the data sequences. It synthesized the correlation and regression analysis of data sequences and could be used to analyze the time lag effect and the relation among several time series. Based on the concept that the downslide thrust of landslide would vary with groundwater level，the measured data of groundwater level could be converted into thrust which induced the change of slope acceleration. And then，the vector auto-regression model which included the measured acceleration of landslide and nominal acceleration stemming from thrust calculated by groundwater level was built. The effect law of groundwater level on surface displacement and the lag time could be estimated by the use of the model. The validity of built model in landslide displacement prediction was verified by application it to the No.6 landslide of Shangyu—Sanmen highway；and it provided reference for similar landslide prediction.

Based on the evident rheology characteristic of soft rock tunnel in high geostress zone，a new support scheme which adds U-steels compressible stent and foam concretes filling layer to the spray anchor network support is proposed. The long-term stability of Xiakou soft rock tunnel with high geostress in Yichang—Badong expressway is studied by using the new U-steel connector mechanical model and contact model between U-steel and surrounding rock in two support schemes. The results show that：(1) The relationship between the compression and friction resistance for U-steel support is well reflected by the built model consisting of U-steel connector mechanical model and contact model between U-steel and surrounding rock. (2) The combined support of U-steels compressible stent and foam concretes filling layer can absorb rheological deformation of surrounding rocks，which reduces the deformation pressure of the secondary lining； and also，it can provide stable supporting force，which is helpful to keep long-term stability for soft rock tunnel with high geostress.

There are a kind of special geological hazard body as namely as frost weathering debris flow in cold mountains in western China. When the projects are built on the accumulation body with large volume or nearby it，it will have great effect on the projects. Taking the five large-scale debris flow accumulation bodies developed along Zhongbo reach of Yuqu River in Tibet as the study objects，we consider that the frost weathering debris flow is a bedrock denudation phenomenon based on engineering geological mapping，analysis of areal geology and collecting of meteorological data，and so on. Its formation is closely related to the particular climate，topography，lithology，structure and earthquake，and so on. and it is gradually accumulated through a few hundred thousand to a few million years. By considering the characteristics of the debris flows accumulation body such as big scale，distribution in groups，bad stability，continuous falling of blocks in the source area，the preventive measures including avoiding and monitoring in some large-scale projects such as Yunnan—Tibet Railway and Zhongbo Hydropower Station are investigated. The results can provide technical support for the project construction and reference for the similar projects.

By analyzing the present image processing techniques applied to deformation monitoring，the advanced target method—subpixel centre detection algorithm is proposed based on the traditional gray weighted detection algorithm and detection algorithm of circle edge. The accuracy test is designed to research its advantages comparing with the traditional algorithms through 4 aspects：target size，camera distance，light intensity，state of target motion. In return，we can get the theoretic accuracy of the method. Based on the features of mark displacement，the new technique of deformation monitoring is put forward. And the applicability test is carried out considering 3 aspects：camera distance，light intensity，state of mark motion. The results indicate that：(1) The subpixel centre detection algorithm with targets can get the higher identification precision with less than 1 mm in shooting distance of 50 m(circle of diameter 15 cm). (2) It is feasible with its sensitivity to catch the mark displacement. When the shooting distance is less than 40 m，the identification error could be controlled to 1.0 mm. And when the shooting distance is less than 25 m，the identification error could be strictly controlled to 0.5 mm. In addition，according to Shicheng—Ji′an highway project in Jiangxi province，the new technique is applied to detect the slope deformation，which testifies its high engineering applicability. The theoretical study and tests confirm the higher accuracy rate，technical feasibility，engineering applicability，and feedback ability in time of the new technique based on the advanced algorithm.

An in situ rock masses triaxial test system YXSW–12 was manufactured by the Yangtze River Scientific Research Institute and Chaoyang Test Instruments Co.，Ltd.. The test system had the following advantages：(1) The real triaxial test could be carried out. (2) The surrounding pressure could achieve 15 MPa；and the axial pressure could achieve 80 MPa. (3) The sample size was 50 cm×50 cm×100 cm，which could express the mechanical characteristic of large scale rock. (4) The complex stress routes could be servo-controlled. (5) The whole curve of deforming and breaking processes could be got，and the deformation and strength parameters in one single test could be obtained. The YXSW–12 test system was used to test the mechanical properties of column jointed rock masses，and got excellent results. The test results were shown as follows：(1) The anisotropic deformation parameters under different loading conditions were obtained. (2) The peak strength and yield strength of original simples were obtained by unloading test. The residual strengths of disturbed samples were obtained by loading and unloading test. The differences of strength parameters with different kinds were compared and analyzed. (3) The break mechanism of field rock masses was researched. The test results indicated that the breaking surface was mainly originated from the column joints. The YXSW-12 test system provides a new means for engineers to find out the deformation，strength and breaking properties of deep and complicated rock masses.

According to the conditions of high intensity rockburst and water gushing of the diversion tunnel in Jinping II hydropower station，the application studies of silica fume(SF) and steel fiber reinforced wet-shotcrete were performed. Samples from batching plant were formed by standard moulds and construction site cutting from field sprayed panels. The SF which contained 10% of cement mass was used as an admixture but not a partial cement replacement. The property differences between SF and steel fiber reinforced wet-shotcrete and concrete and between samples of batching plant and field spraying were studied by comparative test. In comparison with the concrete，the SF and steel fiber reinforced wet-shotcrete had the following characteristics by the results： Under the same slum，the water usage per unit volume increased with the incorporation of SF and steel fiber；the flesh concrete became cohesive；the decrease of rebound ratio became larger；the spraying depth increased；the early strength and ratio between splitting tensile strength and compressive strength increased markedly；the flexural toughness and plasticity improved. Through observation and analysis，we found that steel fiber reinforced wet-shotcrete was not suitable to surface permanent supporting of water tunnels，or else，some measures were taken for the surface of the wet-shotcrete. By comparative analysis，it is pointed out that the testing results of samples formed by standard moulds were different from the cubes cutting from field sprayed panels. And the reasons of the differences has been explored. Finally，some problems needing attention are proposed according to actual engineering application，so as to provide certain reference value for engineering practice.

The precise point clouds of rock surface which are obtained through three-dimensional laser scanning technology are used to get the geometric information and distribution of rock mass fracture networks. Application of penalty function method to disposing seepage boundary condition is put forward while the basic equations and the integration schemes for seepage based on element free Galerkin method(EFGM) are derived. Data for gridding nodes are obtained from coordinate transformation and vacuation of the laser point clouds. EFGM is used for the acquisition of seepage field distribution in accordance with the geometric information and mass discontinuity occurrence. This method has the following advantages：(1) Accurate fracture occurrence，location，length，opening degree and other geometric information for high and steep slope could be obtained. (2) The gridding nodes for EFGM could be directly transferred from the laser point clouds，reducing the work of generating discontinuity grids and coordinates of nodes. (3) Fracture networks are expressed by fracture permeability tensors and simulation of discontinuity with unconnected，different degrees of openings and filling is performed. On this basis，EFGM software LIDAREFM is developed with interactive data language(IDL). The massive laser point clouds handling and numerical simulation of seepage can be implemented by LIDAREFM. The numerical simulation of seepage field distribution for the bare discontinuous rock slope in Qiaozi Town，Huairou County，Beijing is carried out. The results show that the method is feasible and effective and the calculated seepage field distribution and characteristics could correctly reflect the influence of rock fractures on the seepage field of the slope rocks. Meanwhile，this method provides a new research idea for the study of the real seepage field in fractured rock.

Silt-trap dam is an important debris flow preventive measure with a large cubage. According to the forms and circs of the dams summarized and a new notion of the system collocating optimization，the experiment on regulating properties of debris flow by the silt-trap dam has been performed. In the experiment，bulk density，gross and the rate of the drainage hole are changed to analyze the property variation law of debris flow. The experimental results show that：(1) The gradient of intercepted sediments increases with the increase of bulk density and gross of debris flow，and the decrease of rate of drainage hole. The bulk density is smaller，the effects of the gross and rate of drainage hole on the gradient are larger. (2) When the gross of the debris flow is less than the cubage，the value of the flux changing with a drainage hole rate 2.2% is twice to that with a rate 6.6%. (3) Under the same over-current of the drainage hole mode，the former bulk density gets a square formula relation with its ratio to the latter. With the formula，we find that when the bulk density is 1.567 kN/m3，the change of bulk density before and after experiment is the biggest. (4) The ratio of D50 between before and after the experiment is proposed to scale the selection property of the dam and compare the change of grain diameter. The dam gets the most evidently effect of leaving the coarse grain and passing the fine grain when the watery debris flow passes through the dam.

By means of analyzing field monitored data and numerical calculation in Jisan mine，the relationships of drilling crumbs，support pressure and drilling stress are established. Based on this，the real-time monitoring and precaution system of rockbursts is developed. By taking the stress measurement instead of drilling crumbs as main monitoring specifications and monitoring the change rules of stress field at the front of the work face，the continuous and real-time monitoring and precaution for the rockburst dangerous areas and danger severity could be implemented by the system. The self-developed precaution analysis software can display bearing stress dynamic contour and monitoring point stress column. Additionally，the dangerous areas and dangerous levels are estimated by setting the warning threshold value. So，the possible occurrence of rockbursts is predicted. By applying this monitoring and precaution system to some rockbursts mines，it is proved that the system can predict the precautions dangerous areas and dangerous levels accurately. In this way，the secure development of dangerous working faces with severe rockbursts can be done.

The change of resistivity of rock during its damage process is studied by uniaxial cyclic loading and unloading test. The variation rules of rock resistivity，elastic modulus and compression strength in the damage process is found out that it accords logarithmic mathematical model. So the rock damage variable can be expressed in resistivity change. The results of marble triaxial compression test show that the relationship between rock elastic modulus and shear strength accords logarithmic mathematical model；and the difference of the whole variation law is not obvious. According to the research results mentioned above，the empirical equation regarding resistivity，elastic modulus，compression strength and shear strength is established；and the variability of mechanical properties of rock mass can be expressed with resistivity change. At last，the mechanical parameters of disturbed rock mass are estimated according to apparent resistivity change of Donglutian open pit layer in Fushun got by in-situ detection，which provide basic evidence of selecting mechanical parameters for further analysis of the slope stability.

The discontinuous deformation analysis(DDA) method which discretizes the study objects to blocks is a of discrete medium computation methods. The original DDA is based on the small deformation and small rotation assumption which uses time step accumulation to simulate the large deformation and large rotation. So it will produce errors，especially when the large rotation occurs. The DDA program modified by finite deformation theory is conducted；and the results after each time step are modified by finite deformation geometric field. Two examples are carried out to validate the modified code. The results show that the modified code can handle the large rotation problem well and eliminate the rotation error；and it also can be used to solve the small displacement and small rotation problem. The modified code expands the application scope of DDA and can be used as an efficiency tool for engineering calculation.

Effects of number of cycles，preloading frequency，dynamic prestress ratio，density，sampling technique，preshearing mode and duration of confinement on the maximum shear modulus(Gmax) of sand were systematically investigated by applying the preloading to the tested dry sand samples using the non-resonant vibration supplied by resonant column apparatus. Testing results indicated that：(1) The Gmax of dry sand decreased with increase of number of cycles when it was lower than a threshold number. At this threshold number，the maximum reduction of Gmax might be over 20% for some cases. (2) However，beyond this threshold number，Gmax started to recover with increasing number of cycles. The reduction of Gmax with number of cycles decreased with the increases of preloading frequency，dynamic prestress ratio and sample density；but their qualitative relationship was not affected by the sampling method and preshearing mode. The increase of Gmax with confinement duration was minor and the increase rate was slightly greater for the sample with preloading than that without preloading. The variation of Gmax with number of cycles may be accounted for the jointed effects of sample densification，interparticles wear process and particles reorientation or coordination number reorientation.