A series of experiments were carried out with the“multi-functional true triaxial experimental system modeling fluid-solid coupling”to investigate the effect of changing stress Lode angle on the deformation characteristics of sandstone under constant spherical stress and deviation stress( ). The results show that the principal，volumetric and deviatoric strains vary as the stress Lode angle changes. When the deviatoric stress is constant and the spherical stress is variable， ， ， ， and tend to decrease with the increasing of the M(q/p). When the spherical stress is kept constant and the deviatoric stress is variable，the principal，volumetric and deviatoric strains tend to decrease firstly and then to increase with the increasing of M，and the failure of sample occurs when the value of M is relatively large. Some failure planes are parallel approximately to and and perpendicular to . The strength value is significantly smaller than the ones under the conventional loading. The deviatoric stress ratio M has a great influence on the deviatoric strain modulus Gs. The spherical stress affects mainly the volume change of rock. The deviatoric stress affects mainly the rock distortion，and plays an important role in rock failure. The plastic deformation of the sandstone is mainly affected by the Lode angle and the flow direction is equal to .

Rocks in engineering projects experience usually the multistage time-dependent loading before reaching the final stress state. The triaxial compression experiments in laboratory were performed in order to investigate the effect of multistage time-dependent loading on the strength failure and crack coalescence behavior. The tests results showed that all the strengths of sandstone samples with three types of preexisting closed flaw pairs respectively under the multistage time-dependent loading decreased to some extent compared with those under conventional triaxial compression tests. For the type of specimens with high-low angle and high-high angle，the values of the strength under the multistage time-dependent loading were between the initiation stress level ?ci and the critical stress of dilation ?cd. Under the same stress loading path，the fractured rock showed the strong characteristics of shear failure with the increase of confining pressure. All of the low-low angle type of specimens showed the mode of rock bridge failure，indicating that the failure mode of the low-low angle type of specimens is mainly controlled by the distribution of the fracture itself，the influence of stress level and loading path is small. Under the multistage time-dependent loading，the failure of high-low angle and high-high angle type of specimens showed the mode of tensile failure. Burgers model for damage creep was used to analyze the relationship of these rock masses.

In order to study the seismic behaviour of deposit slopes which distribute widely in south-west of China，a generalized model of deposit slopes was designed for the dynamic centrifuge tests with the geometric scale of 1∶50. In this paper，the influence of the amplitude of input earthquake excitations on the dynamic response of a air-dried deposit slope was studied in the 4-stage centrifuge tests and the effect of earthquake acceleration amplification，the deformation mode and the failure pattern of the slope model were analysed. The test results indicated that the horizontal amplification coefficients of peak ground acceleration(PGA) reached the maximum values at the crest，reflecting the amplification effect of altitude. The Fourier spectrum characteristics of input seismic wave were certainly changed along the height. The predominant frequencies corresponding to the Fourier spectrum peak at each measuring point on slope surface decreased with the increasing of PGA. Considering the influence of vertical acceleration amplification，the angle between the direction of the resultant amplification coefficient and the horizontal direction decreased with the increase of the slope elevation，which reveals the phenomena of wave field splitting and waveform conversion. In addition，both the horizontal and vertical amplification coefficients of PGA decreased first then increased considerably as the input acceleration amplitude increased. The failure of deposit slope in the dynamic centrifuge testing was observed to start when the input acceleration increased to 0.216 g. The residual displacements at the crest were obvious and the failure surface appeared to be fairly shallow.

为实现岩石破裂过程的超声波探伤成像–声发射一体化监测，深入研究岩石损伤演化与声发射间的关系。在超声波透射型探测和射线追踪成像理论基础上，从岩石内部区域相关的角度考虑岩石的不均匀性、各向异性，构建了基于声发射AST模式的岩石损伤探测成像方法。着重阐述了损伤探测成像方法的原理、离散速度场的构建、分量速度场矩阵的求解、多分量速度场间复合运算规则、待估物元的搜索方法及最终的损伤探测成像方法。通过选择较为完整无明显缺陷的岩石试件、含有严重损伤缺陷的岩石试件以及存在特殊结构的岩石试件，进行成像方法验证。研究结果表明：基于声发射AST模式的岩石损伤探测法具有良好的探测与成像效果，不仅能定位岩石内部损伤缺陷，还能识别与损伤缺陷相关的弱化区域。该方法可以实现超声波探伤成像与声发射信号的同步监测，为后期开展岩石损伤区域圈定、损伤动态发展的跟踪、岩石破裂动态损伤多指标量化评价、岩石破裂损伤演化与声发射间的关系研究提供了基础。

The tensile and shear failures of rock subjected to high water pressure were studied with the fracture mechanics. For the tensile failure caused by high water pressure，a method was proposed to calculate the stress intensity factors of two symmetric radial cracks emanating from a pressurized borehole. The fracture initiation criterion under the tensile-shear stress condition and the equations for the critical water pressure and the fracture initiation angle were derived. The influence of the perforation angle and length，the radius of the borehole and the difference of the principal stress on the critical water pressure and fracture initiation angle of two symmetrical cracks were analyzed according to the proposed method. The results show that the theoretical calculated critical water pressure and fracture initiation angle are in good agreement with the experimental results. The parameter analysis indicates that the critical water pressure decreases with the increase of the perforation length and the borehole radius. For the shear failure of rock subjected to high water pressure，the shear fracture criterion of both open and closed cracks under the compression-shear stress state was derived considering the effect of non-singular stress component. Finally，the explicit solution for critical water pressure of shear failure under the condition of compression-shear stress state was proposed.

In order to realize the simulation of unloading process of roadway excavation in the laboratory and to obtain the innovative monitoring method，a system that use the cylindrical hollow specimen of rock to simulate the unloading path of the excavation of tunnel rock was developed. The system consists mainly of three independent sub-systems：sub-system I：SAM–3000 microcomputer controlled electro-hydraulic servo rock triaxial test system；sub-system II：the loading and unloading chamber of the hollow cylindrical specimen of rock；sub-system III：Acoustic-Acoustic Emission Integrated Testing System. Through the integration and debugging to the software and hardware of the three subsystems，the indoor simulation of the excavation unloading process of the hollow cylindrical specimen(290 mm in height，200 mm in outer diameter and 100 to 150 mm in diameter) were obtained. The preliminary results of the excavation unloading test to the hollow cylindrical specimen of rock show that the system can effectively simulate and reproduce the excavation unloading conditions on the rock surrounding roadway and can effectively simulate the deformation，stress distribution and failure mechanism of the rock surrounding roadway under the condition of excavation unloading.

A complete description of slope failure should not only be limited to the failure initiation，but also include the development of slope failure and the ?nal con?guration of the slope. This paper introduces a new framework of material point method(MPM) proposed by the authors，including implicit MPM，random MPM and coupled MPM. A series of simple slope simulations under different scenarios are shown，demonstrating the ability of the proposed methods in simulating the observed failure modes and corresponding failure mechanisms，including progressive，retrogressive and super?cial failures due to the rainfall infiltrations，etc. The MPM is shown to be a reliable tool in capturing the large deformations of slopes，including the initial failure and the induced secondary failures，thereby，providing a solid basis for the risk analysis of the slope failures.

The failure modes，dynamic response and stress evolution characteristics of the thick-layered rock slopes with the non-persistent joints in different combinations of rock-bridge lengths and joint spacing were studied based on the two-dimensional particle flow code PFC2D. The results show that the main failure modes of the horizontal thick-layered rock slopes with non-persistent joint under the action of earthquake are collapse failure，tensile-sliding-block toppling failure and tensile-horizontal sliding failure. The horizontal non-persistent joint is the key factor to control the dynamic stability of the slope. The joint spacing plays a controlling role in the failure mode of the slope. When the joint spacing is small，the collapse failure is easy to occur. When the joint spacing is large，the tensile-sliding-topping failure and tensile-horizontal sliding failure occur normally. The length of rock bridge and joint spacing control the degree of rock fragmentation of slope and the number of sliding surfaces when slope fails. When the joint spacing is narrow or when the joint spacing is wide and the length of rock bridge is short，the single sliding failure occurs. When the spacing of the joint is wide and the rock bridge length is long，the double sliding surface damage occurs. Under the action of earthquake，the rock bridge section breaks down at first，and then the joints also produce damage and coalescence. The length of rock bridge and the width of joint spacing have a certain influence on dynamic response of slope. The peak displacement and peak velocity increase as the decrease of joint spacing and the increase of the length of rock bridge. The area with the PGA magnification factor influenced is concentrated at the slope toe and on the slope surface. The stress evolution in the rock-bridge of the slope has a good agreement with the acceleration of the input seismic wave.

A two-dimensional numerical method based on the method of improved rigid body spring and equivalent discrete fracture network model was proposed for modeling of hydraulic fracturing. The interaction between the water pressure and mechanical response was described by Biot?s theory，and the analytic formula of hydro-mechanical coupling for thick-walled cylinder under elastic condition was deduced. The accuracy of the numerical model was verified by comparison with the analytical solution. The numerical model was used to analyze the hydraulic fracturing process of thick-walled cylinders under plane stress conditions. The influence of Biot?s coefficient on hydraulic fracturing process was highlighted. Results show that the Biot?s coefficient，as an important parameter to reflect the hydraulic coupling effect，has the significant effect on the displacement and failure pressure in the hydraulic fracturing process.

The full-range analysis on the mechanical characteristics of bolts in rock mass with bedding separation was performed with the bi-exponential model for anchorage interface to derive the nonlinear solution based on the load transfer method. The full-range mechanical characteristics of bolts including the relationships between the bedding separation and axial force，axial force distribution and shear stress were discussed. Validity of the proposed approach was verified by the experimental results. The results show that the calculated axial strain along the bolts has good agreement with the measured values. During the expanding process of bedding separation，the axial forces of the bolts increase initially and then decrease nonlinearly. The axial force and shear stress distribute unevenly along the bolts，and are transferred to both ends with the expanding of bedding separation. The location of bedding separation affects the mechanical characteristics of bolts significantly. The axial force and shear stress distribute symmetrically when the bedding separation locates at the middle of bolts. Otherwise，the axial force and shear stress show distinguishing distribution and evolution features at both sides，and the shear stress has a jump at the location of bedding separation. The interface with the shorter anchorage length yields the plastic deformation and even slipping failure in advance，which determines the bearing capacity of bedding separation and tensile load of bolts.

In order to overcome the problems in the existing borehole imaging technology based on the assumptions of cylindrical wall surface of borehole and planar imaging，a borehole camera system based on the biconical mirror imaging technology is developed to realize the true three-dimensional imaging of rock structures around borehole. This system is mainly composed of a biconical mirror，a compass，a light source，a hood，a camera and transparent glasses. This paper gives a stereopair imaging method of double-cone mirror for the imaging of borehole wall and the solution formulas to match the panorama stereopair image. The results of system testing and analysis show that this system can obtain the morphological characteristics of borehole and the feature difference of hole-wall details from the imaging of the same borehole structures in two different directions. This system realizes the panoramic stereopair imaging and precise detection of rock features inside borehole with the vision angle up to 360°. The system is simple in structure and easy to implement.

The slope located at the exit of left tail water tunnel of Wudongde hydropower station is a typical bedding slope with a high dip angle，and the deformation occurred in two stages during the excavation. The influences of the slope structure，the excavation at slope toe，the engineering blasting，the fault and the unloading on the slope deformation were studied with the field monitoring and the numerical simulation. The results show that the main reason of deformation is the cutting excavation at slope toe. In addition，the excavation of a tunnel with large cross section at slope toe and the excessive blasting increase the deformation. The small fault in the slope also affects the slope deformation to some extent. Therefore，it was suggested that excavation should be carried out after the slope supporting at the intersection region of tunnel and slope.

The propagation behavior of both main cracks and branched cracks induced by two-hole slotted cartridge blasting with different amounts of charge masses in polymethyl methacrylate(PMMA) was studied by the digital laser dynamic caustics experimental system. The results showed that the main cracks induced by the slotted cartridge blasting grew mostly as mode I and showed the tensile fractures. These main cracks did not penetrate the prefabricated cracks close to the borehole to propagate further. The branched cracks were found initiated from the tips of the prefabricated cracks. The initiation and propagation of branched cracks were induced by the tensile stress concentration due to the blasting stress wave diffraction at the ends of prefabricated crack. The opposite branched cracks started to extend towards each other until their coalescence. The propagation velocity and the dynamic stress intensity factor(DSIF) of branched cracks decreased drastically after the coalescence. When the borehole was with less charge mass，the propagation velocity and DSIF of both the blast-induced main cracks and the branched cracks caused were lower，the branched cracks had longer initiation time and both the steady propagation time and the propagation length were shorter，which prolonged the time of coalescence. The dynamic fracture characteristics of main cracks and prefabricated cracks induced by the equally charged borehole were almost the same. The branched cracks induced by the singly charged borehole did not coalesce.

In order to investigate the effect of the effective stress on deformation and permeability of coal，the strain and permeability of coal cores from No. 9 coal seam of Zhaogezhuang Coal Mine in Kailuan Mine area were measured with the triaxial servo-controlled seepage device. The experiments were carried out under two types of conditions. One type of condition was to reduce the inlet gas pressure while the confining stress was kept constant. Another type of condition was to reduce the gas pressure and confining stress synchronously. The coal shrinkage was found to increase with the effective stress. There was a linear correlation between the volumetric strain of coal and the effective stress within the range of 5.2 MPa and 6.5 MPa. When the effective stresses were outside the range，the stress-strain lines were not straight anymore，and coal dilatation was observed from some samples. The gas flow velocity decreased with the decreasing of gas pressure of inlet port. However the coal permeability increased regardless the decreasing or increasing of effective pressure. Therefore the effect of gas slippage should be considered when the coal permeability change with effective stress is investigated.

Shandong region has complex geological environment and there have been several moderate-strong and strong earthquakes in the history of the region. In order to study the present state of tectonic stress field and the accumulated regional crustal stress level in detail，the characteristics of the ground stress distribution along depth were analyzed with the method of regression analysis，and the accumulated stress level and crustal stability of the region were discussed in accordance with the accumulated crustal stress theory based on the 181 sets of measured in-situ stress data after optimization. The results show that there are mainly two types of in-situ stress states，one is ?H＞?h＞?v and the other is ?H＞?v＞?h，and the type of in-situ stress state is related to the depth. The principal stresses ?H，?h，and ?v increase approximately linearly with depth，and the stress gradients are 0.024 2，0.018 0，and 0.025 8 respectively. The lateral pressure coefficients KH，Kh，and Kav vary approximately hyperbolically with the increase of depth and approach to 1.46，0.89，and 1.17 respectively. The ratio of the half of the maximum horizontal differential stress to the average horizontal principal stress ?d varies linearly with the increase of depth，and approaches to the value of 0.24. The dominant orientation of the maximum horizontal principal stress in the region is overall in NWW-SEE direction，yet a large proportion is in the NEE-SWW direction. The statistical results of the dominant orientation coincide with the World Stress Map 2016 and the interaction of the plates. The dominant orientation of the maximum horizontal principal stress in the west side of the Yishu fault zone is in the direction of NEE-SWW，and that in the east side of it is in NWW-SEE direction. ?m reflects the crustal stress accumulation in the studied area well，and is mainly in the range of 0.3–0.5 and 0.2–0.3. The stress accumulation in this region is in the moderate and low level，and the shallow crust is in a relatively stable state. The values of ?m of the thrust stress state are in the range of 0.2 to 0.3，and the accumulated stress levels are low largely，while the values of ?m of the strike-slip stress state are in the range of 0.3 to 0.5，the accumulated stress level is moderate mainly.

Fracture width and its variation are of great significance to verify the hydraulic fracture model and to guide the fracturing treatment in oil field. Because that the width of hydraulic fracture is 3–4 magnitude orders smaller than its length or height and the reservoir is deeply buried underground，there is no direct method of measurement regarding the width. The width can only be approximately obtained through the estimation of mathematical models and numerical simulations at present. In order to investigate hydraulic fracture width，the transient changes of the width of concrete fracture were monitored by embedding the strain sensors Fiber Bragg Grating(FBG) along the expected path of fracture propagation during the laboratory hydraulic fracturing experiments. The average velocity of fracture propagation and fracture morphology in different moments of time were also obtained with the multiple FBG strain sensors. The fracture propagation process of hydraulic fracturing was described. The research indicated that the width of hydraulic fracture in laboratory experiment reached micron-scale and the velocity reached 0.1 mm/s scale. The fracture width does not increase monotonously along with the expansion of the hydraulic fracture，but fluctuates within a certain range with the intermittent extension of the hydraulic fracture.

The article researched the dynamic response of complex site with tilting strongly weathered layer and local slope with a large-scale shaking table model test. The damage progress of the site was studied through the analysis of marginal spectrum，the strain variations of the soil and the displacement of the slope surface. When the El Centro wave is loaded，the amplification coefficients of acceleration at the points in the bedrock and cover layer increase with increasing of elevation. The amplification coefficients of acceleration decrease with the increasing of amplitude(＞0.33 g). The accelerations at the point in the strongly weathered layer decrease sharply and decrease more with the increasing of earthquake amplitude. When the 3 Hz sine waves are loaded，the energy identification of the marginal spectrum implies that the destruction of the site starts from the strongly weathered layer at the corner of local slopes. Then there appears damage in the strongly weathered layer at the bottom of local slopes and the middle of the site. The destruction of the strongly weathered layer at the corner of local slopes connects gradually with the damage at top. The damage progress is verified by the strain changes in the soil and the displacement changes on the slope surface. The failure modes of the site are cracking-shearing-slippage and cracking-shearing-crushing.

The load jacking the curved pipe roof supporting the large diameter Gongbei tunnel is analyzed. The major components and the impact factors of the jacking force along a curved alignment are discussed. The calculated jacking load based on the design codes of China and Japan is compared with the field measurement and the difference is investigated. The equation for estimating the front face resistance during slurry pipe jacking is recommended. The side frictional resistance and friction coefficient are suggested based on the field measurement to the pipe roof of the tunnel in Gongbei. A formulation for predicting the total jacking force for segmented curved pipe is developed based on the force equilibrium analysis. The analysis shows that the value of unit side resistance and the interface frictional coefficient of steel pipes with lubrication are significantly smaller than that of concrete pipes. The estimated jacking load using the equation derived in this study matches the field measurement well.

The large-scale direct shear test was conducted to soil-rock aggregate with different rock contents，water contents，rock lithology，initial void ratios and normal pressures. The shear strength mechanism of soil-rock aggregate was analyzed through the statistical analysis of fractal geometry of shear surface and the numerical simulation of particle interactions in the direct shear test with the particle flow code. The results indicate that the irregular topography of the shear failure surfaces of soil-rock aggregate are closely related to the existence of rock blocks and presents the fractal characteristics. The fractal dimension increases gradually with the decreasing of water content and normal pressure and the increasing of rock content and strength. If the rock content is more than 40%，the cohesion will be less than 30 kPa. The internal friction angle increases with the increasing of rock content and strength，the decreasing of water content，initial void ratio and normal pressure，and it has a positive correlation with the fractal dimension. The stress concentration happens near the rock particles. In the process of shearing，the contact force between the particles transfer mainly through the surface in the direction of shearing，but the contact surfaces back to the shear direction does not appear to transfer force. The internal friction angle is equal to the sum of   and  ，where   is the internal friction angle of the contact surface of particles on the shear plane related to the particle?s properties and   is the dip angle of the contact surfaces of particles related to the fractal dimension on the shear surface. The variation of shear strength parameters in the shear test can be explained with this mechanism.

In order to explore the deformation of soil due to the rotation of principal stress axes，the following ideas are adopted to establish a model. (1) The results of single shear test on two dimensional aluminum rods are analyzed. The relationship of the ratio of the shear stress to the normal stress(shear stress ratio) with the shear strain is similar to the hyperbolic curve. The Weibull function is adopted to describe the relationship of shear stress ratio and shear strain which describes both the strain hardening and softening. (2) An implicit function about the shear strain is established by combining the shear stress ratio equation in Mohr?s circle and Weibull function. There are three factors influencing the shear strain，including the mean stress p under isotropic or deviatoric compressions， the mobilized friction angle corresponding to the general deviatoric stress state and the half of angle between the shear stress and larger principal stress axe. (3) An incremental equation about the shear strain and shear stress ratio is established by differentiating the above implicit equation. A two dimensional incremental constitutive equation is established by combining the above stress ratio equation and Rowe dilatancy equation. A three-dimensional incremental constitutive equation is derived by expanding the above model adopted by SMP criterion. The compression hardening，shear shrinkage，shear dilation，hardening and softening are reflected in the proposed model(WB). A general stress-strain relationship considering the rotation of principal stress axes is thus derived. The applicability and rationality of the proposed model are verified by comparison of the experimental and calculated results.

Both the nuclear waste container and energy pile buried underground will elevate the temperature and change the stiffness and strength of the surrounding soil，leading to the possible deformation and potential instability of the geo-structure. Despite the extensive investigations into the effects of heating on mechanical behaviour of clay under drained condition，little attention has been paid to the influence of heating on the clay under undrained condition，which is frequently encountered in practice. This paper aims to study the pore pressure response of clay due to undrained heating through both theoretical and experimental investigations. A simplified model base on the framework of critical state soil mechanics was formulated to predict the development of the excess pore pressure of clay due to heating. Two types of clay(Zijingang clay and kaolin clay) were investigated experimentally using a temperature-controlled GDS triaxial testing apparatus. It was shown that the positive excess pore pressure was induced in both normally consolidated and overconsolidated clays subjected to undrained heating. The excess pore pressure increased with the temperature elevation，but decreased with the over-consolidation ratio(OCR). For the normally consolidated clay heated from 20 ℃ to 55 ℃，each temperature increment of 10 ℃ led to a 10% reduction in the effective stress. When the OCR exceeded 10，the heating induced excess pore pressure was almost negligible. The calculated results using the proposed model agreed reasonably with the experimental data，confirming the validity of the proposed model .

This paper presents a shaking table test on slope foundation of bridge reinforced by two rows of anti-slide piles. The dynamic loading applied is the sine waves with different frequencies and peak accelerations. The mechanical responses of the bridge foundation and anti-slide piles and the variation of amplification coefficient of PGA are analyzed. The results show that the distribution of peak soil pressure behind the back row anti-slide piles changes with the peak acceleration of shaking table in plastic silty clay. Due to the small distance between the bridge pier and back row anti-slide piles，the dynamic load affects the bridge foundation greatly，and the maximum strain of bridge pile foundation moves from the pile top to the sliding surface in the loading process. When the peak accelerations of sine waves are the same，the higher frequency of vibration means the smaller of viscous damping and the larger of PGA amplification coefficient in soil. The PGA amplification coefficient of the slope is distributed in layers. Meanwhile，the vibration waves of high frequency cause the smaller displacement and deformation in soil and lead to a smaller landslide thrust. When the vibration waves propagate up in soil，the spectrum of amplitude is magnified near the natural vibration frequency due to the filtering effect.

The longitudinal vibration of a viscoelastic pile was derived by integral transformation method in this paper and the transfer and impulse response functions of pile-soil system were obtained as well. The analytical solution of displacement(velocity) at the pile top subjected to any form of excitation was derived by the convolution of impulse response function and excitation function. This method overcomes the limit of the method of separation of variables considering only the steady-sine excitation and extends the adaptability of the solution. Furthermore，a case study of low-strain integrity testing considering high-frequency disturbing signal was presented. Because of the existence of pile damping，the response to the high-frequency component of testing signal is filtered automatically，and the waveform of subsequently reflection corresponding to the low-frequency component is wide and flat at the same time. When the pile damping is very large，the location of the take-off point of reflection is shifted，and cannot be the basis for the test of one dimensional elastic wave velocity.

Pile foundations of Chalaping bridge in the basically stable low temperature permafrost region and Huashixia test site in the unstable warm permafrost region along the National Road G214 were selected for study. The influence of the pile foundations on the ground temperature was analyzed based on the measured data of ground temperature around the pile foundations regarding the permafrost table，the freezing and thawing processes. The results show that the relatively high thermal conductivity of the pile foundation material accelerates significantly the heat exchange between the ground and atmosphere，which results in the increase of the annual changing range of the ground temperature. The numerical models were established to investigate the long term influence of pile foundations on ground temperature. Under the assumption that the air temperature will rise 2 ℃ in 50 years，the differences of the depth of permafrost table around the pile foundations and in the natural ground will increase，and the permafrost temperature near the piles will rise significantly. This phenomenon is more obvious in the unstable warm permafrost region.

Treatment to the loose strata，such as the excavation(drilling) and backfilling，the pressure grouting and the jet grouting reinforcement etc，should be undertaken to ensure the safety of shield tunneling. A double-controlled grouting method was proposed with two kinds of controllable slurries(controllable filling and controllable cement paste slurry) based on the controllable characteristics of traditional grouting process through sleeve valve tube. The proposed method is very handy to operate in practice and easy to lift the pipe. The range of reinforcement is controllable and the appropriate strength of reinforced solid can be achieved. The diffusion equation of the controllable grout in soil strata was derived and a formula for the slurry control in grouting process was derived according to the operating principle of double-controlled grouting. The method was applied to the shield tunneling in loose strata of a river-crossing project successfully. The results of the study and application show that the continuity and integrity of stratum is improved significantly after the grouting treatment. The drilling process of inspection hole is carried out smoothly in reinforced area，the core samples have the structural integrity and the compressive strength and permeability coefficient of the samples meet the design requirements of reinforced solids after 28 days. To achieve the optimum effect of grouting，a single injection height should be controlled within 15 m，the distance of radial diffusion should be less than 25% of the distance between the arrayed holes，the plastic strength of the controllable filling should be controlled in 0.3 MPa to 0.5 MPa.

The squeezing effect of plastic tube cast-in-place concrete piles(TC pile) was investigated by combining with three technologies of transparent soil，particle image velocimetry(PIV) and close-range photogrammetry. The soil deformations caused by TC pile installation were explored and compared with those induced by conventionally jacked pile. The test results show that the maximum displacement caused by casing jacking for expanded-conical-base pile is decreased by 40% compared with that for expanded-flat-base pile. The affected zone extends as far as 11 times the radius of pile shaft at the surface in the case of the flat shoe，whereas in the case of the conical shoe，the affected zone up to 6 times the radius of pile shaft from the pile centerline. The soil movement caused by casing extraction occurs mainly in the early stage of extraction. The maximum displacement and affected zone caused by casing extraction for the conical base are about 57% and 33% of those for the flat base respectively. However，during the jacking of TC pile，the casing driving is the dominant factor causing the soil deformation，while the recovery of soil deformation caused by casing extraction is small. The displacements generated by jacking a conventional pile with the same diameter is consistent with those induced by TC pile installation，but its affected zone is slightly smaller.