A new model and method of identification precursor information was presented based on the monitoring of ground sound to provide an early warning of rockburst. Using the actual monitored data of ground sound as the training samples，eleven multidimensional feature vectors characterizing the rockburst hazard precursors were obtained from the ground sound signals in a fixed time window by the method of time-frequency domain feature extraction. A new support vector machine(SVM) learning method was applied to solve the training problems with imbalanced data sets in the application of large-scale engineering practice and to improve the classification accuracy and the training speed of SVM. Adopting the measured data as the learning samples on SVMs for training and establishing the appropriate precursor identification model，the accuracy reached 93.87%. Experiments show that this method is effective and reliable，and which is capable of fast sample identification meeting the online monitoring requirements.

The method of decision-level fusion based on Kalman filteration was used in order to reduce and even eliminate the errors in multi-sensor monitoring and to correctly evaluate the geological characteristics of a landslide in Southwest China. The data of horizontal and vertical displacements were analysed. Results show that the landslide had experienced stages of slow deformation，uniform deformation，accelerated deformation and rapid deformation. It indicates that the landslide is a stepped process of variation. The rainfall infiltration is the main factor. The Kalman filtration fusion theory reduces the limitations of traditional methods by making use of the fusion method. It eliminated the ambiguity of the data collected by sensors. The feasibility and effectiveness of the method are confirmed.

Further excavation beneath the basement of an existing building is likely to change the loading stiffness of the virgin pile-soil system，thus affecting the post-excavation pile behavior. In this study，Mindlin?s solution for additional stress allowing for the variation of vertical effective stresses induced by excavation around a single pile was used. The ultimate shaft and base resistances of a pile before and after excavation were calculated according to the stress solutions. A case study was carried out on the basis of the load transfer functions of hyperbola-type along the pile shaft and below the pile base. The study involved the variation of the system stiffness and the load-displacement curves for pile-head due to excavation. Discussion was focused on the variation of reduction factors of bearing capacity with the control values of settlement，and the variation of reduction factors of the initial rigidity and the ultimate resistance with excavated depth and unloading ratio. Results show that the initial rigidity and the ultimate resistance decreased with the increasing of excavated depth，varies inversely with the unloading ratio and are smaller for weaker soils. For a given excavation depth，the decreases of the initial rigidity and the ultimate resistance are more prominent along the pile shaft than beneath the pile base，particularly for the initial rigidity. The reduction factors for bearing capacity increase with the increasing of control values of settlement until a constant value is reached.

In order to repair the collapsed shaft at the watery zone with fault fractures in a new mine in Yunnan province，the basic principles and the“sequence-combined”control method were put forward based on the callapsing mechanism of shaft rocks obtained through on-site research and numerical simulation. The fundamental reasons of the instability and slippage of shaft rocks were found to be the serious degradation of the surrounding rock by water，the low capability of self-supporting and the distinct plastic fluidity of loose rocks in the watery zone with fault fractures. Previous multiple unsuccessful repairing led to the increase of the caving height，the activation of the fault fractures and the unblocking of the local aquifers and caused large area collapses and water gushing in the broken section. The broken surrounding rock during the process of instability and slipping had a zone of quickly release of stress，a zone of transition of stress and a zone of stress concentration. The key measure of controlling the surrounding rock is to block water flow and to reinforce the rock in the zone of stress relieved and containing groundwater flows for improving support ability of the surrounding rock and decreasing the support loading in the following stage. Variation angle umbrella-like ahead grouting are proposed to carry out from a distance behind the deformed area. The temporary support can provide the space and the time for the first and/or the secondary support later. The integral supporting capacity of the surrounding rock can be improved by embedding grouting pipes so that the secondary grouting can be applied to backfill the cavities which may exist in fractured surrounding rock.

A series of new specimens were proposed for testing the toughness of mode I fractures：flattened ring with edge cracks，semicircular flattened ring with edge cracks，edge cracked semicircular flattened disc，and their counterparts without flattened ends. Finite element method was used to calibrate the dimensionless stress intensity factor of these specimens and analyse and curve fit the variation of the stress intensity factor. The results reveal that for the edge cracked(flattened) ring，the curve of dimensionless stress intensity factor versus dimensionless crack length appear to be ascending succeeded by descending；so the critical point can be identified directly from the corresponding load-displacement curve based on this unique property，bringing convenience for measuring the material?s fracture toughness. The edge cracked flattened semicircular disc also has such property，but wider flattened ends should be chosen. While the edge cracked semicircular disc and edge cracked(flattened) semicircular ring do not have this unique characteristics. In addition，in the preliminary experimental test，the fracture toughness of a sandstone determined with the edge cracked flattened semicircular disc and the edge cracked flattened semicircular ring coincides respectively with the results derived with the specimen suggested by the International Society for Rock Mechanics.

Mutually demolishing and eroding occur between the alkaline reinforcement material and the acidic laterite. The alkali erosion tests were designed for laterite based on the chemical analysis of the materials and the principle of life acceleration. The content changes of the effective ions representing the losses of crucial substances in laterite were detected from the leachate from the eroded laterite of the control experiments. Main engineering indices were tested on virgin and eroded laterite to obtain the degradation of the engineering qualities of laterite. The relationships between the ion contents and the engineering indices were established and analysed. The relationships between the engineering indices and the losses of chemical substances were studied using the stepped regression analysis of multiple variables. The effect of effective ions on engineering quality was thoroughly discussed with the relationships derived. Significant quantitative correlations exist between the changes of main engineering indices and the losses of chemical substances in laterite eroded by alkali. Degradation mechanism of the laterite eroded by alkali was revealed，which may be useful for analyzing the speed and trend of deterioration in laterite engineering.

Under the assumption of pure slip contact along the lining-rock interface and the requirements of the net size and the lining thickness，derivation of shape optimization of a tunnel support was carried out with the objective of the greatest tangential stress along the inner edge of the support being minimized. The optimizing process is to solve a class of inverse geometry problems，and the corresponding forward problem can be solved with the method of conformal mapping of complex variable function in plane elasticity. During the process，the tangential stress along the inner edge of the support was selected as the objective function and coefficients of the mapping function were taken as the design variables. The method of mixed penalty function was used to minimize the objective function. As the objective function reached the minimum value，the optimal shape of support can be obtained. With the optimal shape，stress state in tunnel support was improved most effectively and the tangential stress concentration along the inner edge of support was minimized.

The measured data of the surface deformation including the horizontal and vertical displacements in the west part of Chengchao iron mine over the period of 6 years were collected and analyzed. The contours，moving line and collapsing line were expanded the most in the northeast area of the iron mine from the initial time of surface subsidence up to now. In January 2010，the displacements of rock mass at a road in mining area，at the surface of the fines yard and at the surface in the southeast of the transportation tunnel were found to accelerate. The reason was that horizontal stress in mines was greatly released，especially in the northeast of the mine. In the mine road and fines yard，bending fracture plane was formed in deep rock mass，and now it entered the stage of toppling-sliding to golf along the high and steep dip angle of tension cracks，with the surface deformation increasing rapidly，while in southeast area of transport tunnel，only certain bedding deformation occurred in deep rock mass. After a shorter but rapid phase of increasing，the deformation became increasing linearly and steadily，and the rock mass there is entering into a stage of toppling failure. The research results may be applied to the similar metal mines for reference.

In order to understand the impact of stress interference caused by the artificial open cracks on the formation of complex fractures of subsequent fracturing，and to guide the optimal design of shale fracturing，a model of stress interference of artificial fractures was established based on the homogeneous and isotropic two-dimensional artificial fracture model. The model considered the displacement discontinuity with the cracks of unequal half-lengths，unequal spacing and arbitrary angles of inclination between cracks and horizontal wellbore  to study the feasibility of the formation of complex fractures with different perforations，crack parameters and original principal stress on the basis of geostress conditions. The calculated results indicate that the staged multi-cluster perforation and simultaneous multi-cluster fracture initiation have stronger stress interference for developing complicate fractures than the single-stage perforation and single stage fracture initiation do. The longer length the open cracks，the larger the net pressure and the stronger the interference of fracture induced stress，the greater the possibility of complex fractures formation by the subsequent hydraulic fracturing. The optimal crack spacing between the formal open cracks exists for the formation of complex fractures. Besides，if the difference between the original maximum and minimum horizontal principal stress is too large in shale reservoir，then it?s hard to achieve the geostress condition of complex fracture formation effectively even with the crack interference. So，forming complicate fractures by hydraulic fracturing should not be regarded as the main tool of reservoir stimulation.

Rocks exhibit different strain-softening and dilatancy behaviors under various confining pressures. For tunnel excavation，the method to obtain the stress and strain states considering variability of the confining pressure in the plastic zone is different from those in the existing studies. According to the variation of critical plastic shear strain of the strain-softening rock mass influenced by the confining pressure，a modified criterion was presented to determine whether the rock mass resides within the plastic residual zone. A nonlinear dilatancy model was introduced to account for the confining pressure and the critical plastic shear strain. The plastic softening and residual zones were divided according to a certain radial stress increment. The stress and strain components are obtained based on Hoek-Brown failure criterion with the finite difference method. In order to discuss the influence of the confining pressure on the rock mass stability，four nonlinear mechanical models were established according to whether the critical shear strain or dilatancy coefficient was changed or not. The critical plastic shear strain，the dilatancy coefficient and the rock mass deformation in the plastic softening and residual zones were further studied under the four models. The calculated results show that for lower geological strength index(GSI)，the stress and strain states considering the confining pressure distinguish greatly from those not considering it. A reduction of the critical plastic shear strain restrains the dilatancy behaviour of surrounding rock mass near the opening surface to a certain extent.

The deformation characteristics of the foundation of medium-strong expansive soil under low embankment upon soaking was studied for the construction of Yun-Gui high-speed railway. The field soaking tests of expansive soil foundation under the subgrade of different heights were carried out using the artificial soaking with sand holes，sand traps and sand cushion etc. applied together to have multidirectional soaking during the test. The deformation of the ground surface and the subgrade surface were measured during the stage of embankment construction，the steady stage after the construction and the artificial soaking stage. The measured results indicate that the curves of deformation of expansive soil foundation can be described as S-shaped curves from the beginning of subgrade filling to the end of artificial soaking. Along the cross-section of subgrade，the expansion variables can be decribed as “pan bottom” shaped distribution on the ground surface and as V-shaped distribution  on the subgrade surface. The relative expansion of the ground surface decreases linearly with the increase of the height of embankment. The relative expansions of the ground surface are larger than those of the subgrade surface. The expansion of the ground surface became smaller and smaller as the height of subgrade increased. On the basis of these experimental results，the critical height of the subgrade that lead to the zero swelling at the ground surface is thus proposed to be the control value for the design of the embankment.

The frequency and intensity of the accidents of rockburst in deep coal mining，coal and gas outburst and other dynamic disasters have been increasing continuously. These types of accidents are often mutual stimulating and transformable，which lead to a very complex mechanism of disaster yielding and difficulties in its monitoring，early warning and prevention. The accurate prediction the type and the grade of dynamic disasters is necessary prerequisite for disaster prevention and curing. During the development process of a dynamic disaster，deforming and fracturing of coal or rock and gas migrating produce a large quantity of electrical charge in coal rock. Studying the characteristics of the information of the charge radiation of different types of dynamic disasters in the breeding process can provide clues to accurately predict the rockburst disaster. A coal charge monitoring system was installed to measure the charge radiation signal in the coal rock around the side roadway ahead of the working face. Measured charge radiation was analyzed. The charge signals were stable and smaller when the working at the normal operating period. Precursory anomalies were visible before the dynamic disaster. The characteristics of the charge signals were prominently different for different forms of dynamic disasters. In the course of outburst，the values of the maximum charge increase with large fluctuations，the values of the minimum charge was nearly zero. For the rockburst in the breeding process，the value of the maximum charge was largely the same with the minimum one varying in a higher level steadily without obvious fluctuation. For the compound dynamic disaster，the maximum values of the charge radiation were at a high level with larger fluctuation and the minimum values of the charge radiation was at a high level relatively stable，which appeared to have both the features of gas outbust and rockburst. Therefore，the charge radiation of the coal rock can be used not only to forecast the dynamic disaster risk of coal and rock，but also to judge the type of disaster for the control measures to be taken accordingly.

In 2008，the Mine-by(MB) Niches were constructed in Mont Terri underground rock laboratory. One of niches，MB Niche2，was selected to investigate the deformation and the coupled hydro-mechanical behavior of the Opalinus clay near excavation. Based on the engineering geological conditions of MB Niche2，a geomechanical simulator incorporating the two-part Hooke?s model(TPHM) was employed to simulate the excavation process of MB Niche2. Numerical results show that near the roof of Niche recorded a maximum of 10 mm of inward movement. Near sidewalls，the damage zone developed up to an average distance of 1.4 m into the rock matrix. Pore pressure increase became visible at about 11 m ahead of the mine-by excavation face. With niche advancing，the zones with local higher pore pressure are mainly found near the edge of the damage zones. The maximum pore water pressure reaches about 3.3 MPa near the advancing face of excavation. Compared with those based on the conventional Hooke?s law(SPHM)，the results based on TPHM are more consistent with the field data sets，which indicates to some extent that TPHM can better capture the physical nature of natural strain(true strain) in porous and fractured rocks and highlights the importance of having appropriate conceptual and numerical models available that accurately capture the complex coupled behavior in response to excavation.

Gongjiafang slope #2 is a counter-tilt slope consisted of thick/thin and soft/hard rocks layers at Wuxia Gorge section in the Three Gorges Reservoir area. It had undergone a complicated failure process of bending to slipping. In order to study its failure mechanism and criterion，the rock structures of the counter-tilt slope were investigated and its deformation process and failure mechanism influenced by rising water level of the reservoir were analyzed. A set of analysis models，i.e. superposed cantilever model，independent cantilever beam model were proposed to decide the failure criterions of the counter-tilt slope by comparing the slope stresses with the rock strength. The finite element method was employed to analyze the parameter reduction of rock and the laws of deformation and failure. The strata structure of the upper hard rock strata and the lower soft rock strata and the deep and steep river are the key reasons to induct bending deformation onto the counter-tilt slope in the Wuxia Gorge area. The counter-tilt slope with different layer thicknesses has multiple failure stages and different criteria with the superposition cantilever model appropriate for thin soft rocks and the independent cantilever beam model fit for thick rocks. The shear strength of thin marlstone may be reduced to 85% of its normal strength after the rock softening and the slope failure developes from the lower part to the upper part.

Based on the experimental results of intact red sandstone under conventional triaxial compression，a set of microscopic parameters in particle flow code(PFC) reflecting the macroscopic mechanical behavior of intact red sandstone were obtained by analyzing the sensitivity of microscopic mechanical parameters in PFC. The particle flow simulation was carried out for the red sandstone containing two pre-existing fissures under different confining pressures. The influences of the confining pressure and the ligament angle on the strength failure characteristics of the red sandstone containing two pre-existing fissures were analyzed on the basis of the simulated results and the microscopic mechanical mechanism of crack coalescence of the red sandstone containing two pre-existing fissures was revealed. The parameters of peak strength of red sandstone containing two pre-existing fissures are smaller compared with that of the intact red sandstone，and the extent of reduction is related to the ligament angle β. The cohesion and the internal friction angle varied both nonlinearly with the ligament angle ?. When ? were 0°and 30°，the ultimate failure modes of the red sandstone containing two pre-existing fissures were similar to each other，no coalescence was observed between fissures ① and ②. When ? are 60° and 90°，the ultimate failure modes were similar，one crack coalescence was observed between fissures ① and ②. If ? was 120°，two crack coalescences were observed between fissures ① and ② at lower confining pressure，but only one crack coalescence occurred at higher confining pressure. When stress increased to a certain value，the bonds among grains began to break. The newborn micro-cracks initiate，propagate and coalesce to form the macro-cracks which results in the unstable failure of rock specimens. The increase of confining pressure improves the contact and bond force among grains at the microscopic scale，which leads to the increase of strength at the macroscopic scale. Existence of high confining pressure limits the propagating speed of microscopic cracks.

The delayed signals and external outlier signals are two common outliers which seriously affect the accuracy of microseismic source locating. In order to recognize them efficiently，the hyperbolic and hyperboloidal governing equations were obtained based on the theory of microseismic source locating and the geometrical characteristics of network layout. The source paths from different source location methods were found to be a series of hyperbolas on a plane or hyperboloids in a space；and the shape and the position of hyperbolas or hyperboloids were closely related to the time differences of arrival. The study showed that there were theoretical limits of time differences of arrival for P-wave and delayed wave respectively. A model to derive the two type of theoretical limits of time differences of arrival was established on the analysis of the time differences of arrival and the geometrical characteristics of microseismic network and monitoring space. A table of the time differences of arrival for outlier signals analysis was constructed. A novel method was thus put forward for recognizing the delayed signals and external outlier signals. The feasibility and advantages of this method were verified by an in-situ blasting test. The experimental results show that the delayed signals and external outlier signals are identified correctly and effectively by this novel method. The accuracy of microseismic source location is improved greatly after eliminating the outlier signals.

In order to explore the fatigue properties and its influence factors，an evolution model of damage accumulation was established and the effect of static loading on the damage accumulation of rock under cyclic impaction was studied. Compared with the S-shaped growth curve，a model of the damage evolution of rock having a trend of rapid rising，steady development and sharp rising subjected to the coupled static-cyclic impact loadings was established using the inverse transformation of logistic function. The physical meanings of the parameters in the damage accumulation model were determined by analyzing the variation of the curves with three parameters fixed and one varying. The objective function for fitting the damage model was established based on the approximation theory of the least squares. After programmed with Matlab，the data fitting of the damage accumulation model was calculated and the damage accumulation model was proved to be correct by the test data. The evolution model of damage accumulation was used to fit the experimental data of rock damage upon cyclic impaction under different static loadings. The effect of static loading on damage accumulation was studied through analyzing the relation between the fitting parameters and the static loadings. The axial pressure and the confining pressure have great effect on the trend of dynamic fatigue damage of rock. The change of axial pressure has smaller influence on the parameters ?，? and ? with the confining pressure increasing. The change of confining pressure always influences evolution the trend of dynamic damage accumulation no matter how much the value of the axial compression is.

In-situ dynamic tests on cutting subgrade of expansive soil were carried out to investigate the dynamic characteristics of the cutting subgrade with different waterproof layers under extreme service environments. the results show that service environments were found to affect the values of dynamic characteristic parameters (dynamic stress，velocity and acceleration)，and that the attenuation of the dynamic characteristic parameters is related to the stiffness of waterproof structure layers. Compared to that of the subgrade section with the waterproof layers of cement-based compound material，the dynamic displacement of the subgrade surface with the compound waterproof plates is bigger. The modified cement-based waterproof structure layers has large stiffness and excellent anti-permeability，which would desirably solve the problems of lap seam leaking and the mechanic damage of the compound waterproof plate in the process of building，and this is important to the long-term stability of the cutting subgrade in expansive soil area.

The mechanical properties of clastic rock of dam foundation in a hydropower station in virtue of conventional physical and deformation analysis are very complex. Triaxial rheological tests were therefore conducted using the automatic triaxial servo-instrument to investigate the rheological properties and permeability of such rock under hydro-mechanical coupling. The axial，lateral and volumetric deformation curves versus time were measured and the rheological deformation properties and rheological rate law were discussed accordingly. The evolution process of permeability during rheological period was analyzed in detail. The scanning electron microscope(SEM) experiments were performed for the rock specimens after failure to study the mechanism and mode of macro-micro failure. The results show that the clastic rock has a pronounced rheological behavior. The rheological curves have a transient period initially，a steady period thereafter and an accelerated period finally at the last loading step. The rheological deformation were increased when the stress and seepage pressure applied were increased and were reduced if the confining pressure was increased. The finally failed specimen have the characteristics of large axial compression deformation，obvious ductile volumetric dilation and large steady rheological rate. The relationship between the rheological rate and the applied stress can be described by an exponential function. The coefficients of permeability fluctuate during the rheological process possibly because of the heterogeneity of specimens，but overall decrease. During the stage of steady period，the coefficients of permeability decrease linearly. It is shown that the fluctuation has no significant effect on the permeability evolution. Furthermore，the permeability coefficients decrease as the confining pressures increase.

The large scale in-situ test is an important method to solve complex engineering problems. During the construction of diversion tunnels at Jinping II hydropower station，an in-situ test program to monitor the realtime response of the surrounding rocks of the diversion tunnel excavated with TBM was designed and implemented. The contents of the in-situ test program include the stress measurement of rock mass with the rock stress meters of vibrating wire and CSIRO HI Cells to record the stress change in rock mass during tunneling，the acoustic emission monitoring to detect the crack initiation and propagation in rock mass during excavation，the sonic velocity measurement to determine the profile of excavation damage zone around tunnel，the displacement measurement with the multipoint displacement meters and fiber Bragg grating sensors to obtain the deformation of rock mass during tunneling，the digital photographing of borehole to observe the process of the macrocrack initiation. This article is the first of the series and introduce the background of the project，the designing of the in-situ test program，and the detailed geological models of the tested region.

This paper presents the in-situ test results on the basis of the previous research. The in-situ tests showed that the deformation，the stress change and the microcrack initiation occurred in the the rock mass at didtance of 1.2 times of the diameter of diversion tunnel ahead of the excavation front，and the stress changed greatly in the rock mass 2–10 m behind tunnel front. The data of acoustic emission indicated that the rock mass in the range from 5 m ahead of the tunnel frount to 10 m behind the tunnel front produced the most acoustic emission energy during tunnelling and the acoustic emission was largely stable when the tunnel front was 10 m ahead of the acoustic emission monitoring section. The results of the optical fiber Bragg grating monitoring indicated that some closed cracks the rock mass close to the wall with serious excavation damage and subcritical crack growth reopened or further propagated even when the tunnel face effect disappeared. The most serious excavation damage occurred on the right spandrel and the damage zone was about 3 m in depth. The results from the multipoint displacement meter monitoring showed that the deformation of surrounding rock during tunnel excavation was not siginificant. The monitoring of deep tunnelling should therefore mainly focused on the measurement of excavation damage zone，stress in the rock bolts，stress in rocks，optical fiber Bragg grating and acoustic emission measurement and supplemented with a small number of multi-point displacement meters.

The durability problem of anchor rods used to reinforce slopes can be solved by substituting fiber reinforced polymer(FRP) bars for steel bars. The FRP bars have small elastic moduli，and therefore should be prestressed in order to limit the deformation of the reinforced slope during its service stage. This paper described  the grating sensing technology to be applied to monitor the bond behavior of sand-coated GFRP anchor rod under cyclic prestressing. The results showed that prestressing of the sand-coated GFRP anchor rod led to the damage of rod-mortar interface bonding of the anchor. The effect of repeated load on the bonding was negligible and the effect of the surcharge load was significant. The damage to the bonding of rod-mortar interface of the anchor is dependent only on the surcharge load，and not on the service load. The shear force of the anchor rod is provided by the bonding force and friction；with the bonding force generated at the initial stage，and then changed into friction at the later stage. The excessive peak loading leads to the damage to the bonding and the loosening of the anchor structure. The over tension load of the prestressed anchor rod structure must exceed the service load to an extent in order to ensure a stable anchorage force in the service stage.

With newly-built experimental equipment，tests on 100 mm×100 mm×100 mm granite specimens under vertical static stresses with lateral disturbance have been conducted. Numerical simulation with software PFC3D was used to reveal the inner mechanism of failure. The acoustic emission(AE) system PCI–2 was used to pick up AE signals. It?s found that the peak AE energy event usually happened at the unloading stage of the disturbance stress. The peak AE energy event tended to happen earlier and more frequently with the increase of the static stresses. Wave velocities at different positions were used to evaluate the damage distribution of the specimen at different loading conditions. RA values were also used to investigate the failure mechanism of specimens. When the static stress was low，only few shear cracks were triggered and a small shear failure zone was observed at the direct contact zone of the disturbance load. When the static stress was high，the shear cracks and the tensile cracks were both activated and the proliferation of tensile cracks resulted in the structural failure of specimens eventually. Numerical investigation also demonstrated this phenomenon.