Abstract：As a numerical modeling approach，discontinuous deformation analysis(DDA) method was employed to analyze effects of different factors on the deformation characteristics of an underground powerhouse. The effect factors mainly consist of stress lever coefficient，rock reinforcement，joint structure pattern and strength properties of joints in surroundings，etc.. It has been shown that DDA model can get reasonable results with different simulation cases. The deformation of surrounding rock mass is closely relevant with rock stress conditions assumed beforehand. As the surrounding rock mass has the characteristics of hard and soft rocks being formed alternatively，where the multi-layer of shear zones exists between them，the displacements of sidewall have larger increasing intervals compared with those of roof arch displacements of the powerhouse when horizontal stress increases；and the discontinuous sliding along surfaces of shear zones will occur normally. Reinforcement with rock bolts will bring favorable effects on rock surroundings in controlling deformation and stress distribution properties. If a series of key blocks collapse，the joint intersections in surrounding rock mass，in some cases，will exert negative effects on the stability of powerhouse. On the other hand，for joint intersections being under stable state，unstable deformations of rock surroundings will occur when the joint strength is reduced to some extent. This paper presents some relevant results with DDA method，and some problems associated with DDA have been discussed.

Abstract：There are some damages and separating deformation in the roof of Longyou grotto No.5. According to in-situ investigation and measurement，separating deformation of roof at the grotto exit accumulated to 75–78 mm，and there are damages and fracture phenomenon like cantilever beam at lateral side of grotto roof. In order to understand the fracture process of the roof for grotto No.5 and long-term stability，the numerical simulation and back analysis of rheologic fracture are carried out by using in-situ damage pattern and deformation data，based on the tracking method of maximum tensile stress and the back analysis of rheologic fracture presented by the authors. In the process of back analysis，the orthogonal experiment is used to design 27 kinds of the schemes of numerical simulation. The optimum scheme of parameters which are composed of the rheologic parameters of rock layer，thin double-layer and other sensitive parameters is obtained by analyzing the orthogonal experiment results. The long-term stability and the process of rheologic fracture are analyzed by utilizing the obtained optimum scheme. The calculated results show that the separating deformation of the roof at the grotto exit is 54.24 mm and the fracture location is same as the location of in-situ fracture. In addition，the separation deformation of roof at the grotto recess is also very obvious in rheologic numerical simulation；and the phenomenon is similar to the apparent form of in-situ deformation.

Some simplified models are studied and discussed about the vertical movement and segregation of asthenosphere rock and the residue of partially molten magma under the guidance of the hypothesis of creep flow of mantle and alternation of thermal energy concentration-diffusion，which belongs to the activation tectonics theory (the DIWA theory). Firstly，some assumptions are made to get a kind of simplified dynamical formula according to the basic principles of rheology in a porous medium. Secondly，the formulae are nondimensionalized by introducing some parameters；and the dimensionless models are studied and discussed in detail. Then according to the results of the models，it is only in some regions that the deformation of the rock media could affect the transportation of partially molten magma，in which the dynamical characteristics of models should be adopted by modified Darcy¢s law，and beyond which the results of the transportation using classical Darcy¢s law are accurate. All these conclusions show why the metallogenetic mass could move upward from the asthenosphere to the earth's surface，which is corresponding to the geology background，and magma transport might be of importance for the further research of rock creep and the dynamics of ore-forming processes.

Abstract：The well-known empirical e-lgs ¢ relation is introduced into the study on one-dimensional nonlinear consolidation of one-layered soil under cyclic loadings. The corresponding consolidation equation is established with the assumptions that the decrease in permeability of soil is proportional to the decrease in compressibility during the consolidation process and that the distribution of initial effective pressure does not vary with depth. The analytical solution is then developed for the nonlinear consolidation problem under low-frequency trapezoid cyclic loading via the w -s ¢ transform；and the relevant computer program is developed by Fortran programming. In addition，the obtained nonlinear analytical solution is verified through comparing it with the known analytical solution corresponding to special cases and with the semi-analytical solution，respectively. All the relevant analytical solutions so far available for 1D nonlinear consolidation are special cases of this solution.

Abstract：The effects of various lengths and location of deeply buried piles on the stability of a slope are simulated by nonlinear finite element method with shear strength reduction. Conclusions are made from the simulation results as follows：(1) the slope can acquire effective stability by deeply buried piles as other reinforcing structures；(2) when the length of the deeply buried piles is relatively short，the critical slide surface will slip along the top of the pile；and (3) the location of slide surface determines safety of the slope. As the pile length increases，a secondary critical slide surface will displace and the safety factor of the slope will increase. If the location of the secondary critical slide surface is unchangeable with pile length increase，the safety factor of the slope is also unchangeable. Distribution of the internal forces in deeply buried piles is more reasonable than that in traditional full-length piles；and both the maximum bending moment and the maximum shear force in deeply buried pile are much less than those in full-length pile. Deeply buried piles will be widely used in stabilization of slopes. The applications to deeply buried piles are restricted with the ratio of the strength of slide mass with that of slide area，the site of secondary slide surface，and the length of deeply buried piles. It would lead to failure if the limitations of deeply buried piles stabilizing the slope were not considered in the design.

Abstract：It is an important significance in the technique development of fully-mechanized caving face(FCF) to develop the large-section gob-side entry retaining in FCF，but the stability control of surrounding rock of large-section gob-side entry retaining in FCF becomes a technically difficult problem；and its support ways will endure the test of large deformation，which probably has an influence on the stress state of bolt in traditional bolt supporting. The software ANSYS is applied to simulate the shearing deformation characters of bolt through roof in gob-side entry retaining and the rule that shear stress of the bolt changes with turning angle of main roof and obliquity of the bolt distribution is noted. The result indicates that the roof support bolt has obvious shearing deformation in the course of huge deformation or even shearing fracture if the traditional designed large-section gob-side entry retaining in FCF is adopted. If the design scheme of bolt supporting is adjusted properly，i. e.，the inclination of roof support bolt is adjusted properly，the shearing force that the bolt is supported will reduce obviously，whose effect has been verified by the physical simulation and the underground industrial test.

Abstract：As a simplified analytical procedure，the shear-beam or shear-slice model is widely employed for evaluating dynamic response of earth dams or embankments. In order to improve the accuracy or extend the range of this simplified model，many efforts have been made in the past several decades. A modified equivalent linear technique for analysis of seismic response of embankments，which is based on one-dimensional shear-slice model is presented. In the proposed method，the discrete shear-slice model is developed to consider the layered distribution of shear moduli and damping ratios of soils with depth. The differential equations for governing the vibration of embankment are solved mathematically under the assumption that the soils of embankment display visco-linear-elastic behavior；and the closed-form solutions for the natural characteristics and seismic response of the embankment are obtained. The achieved linear solutions are incorporated with equivalent linearization technique for seismic response of embankment or soil strata. A series of trial-and-error iterations are performed to make the moduli and damping ratios of all individual layers be compatible with their strain amplitudes. Then，a linear system which is overall equivalent to nonlinear embankment system is achieved；and the seismic response for this equivalent linearization system can be taken as a good approximation of nonlinear seismic response of embankment. Finally，numerical computations are conducted for a given example and the numerical results are compared with the solutions obtained with finite element method to illustrate the rationality of the proposed method.

Abstract：Based on the mathematical models of seepage failure risk and slide instability risk for levees，the mathematical models of sandy soil seismic liquefaction risk and comprehensive failure risk for levees were developed；and the conception of risk management for levees was established. The risks of seepage failure，slope slide instability，sandy soil seismic liquefaction and comprehensive failure in Banqiao River levee were analyzed；and critical risk coefficients for seepage failure，slide instability and comprehensive failure in Banqiao River levee were found on the failure case of Banqiao River levee in 1995. In addition，according to the results of risk analysis，and approaches of risk management，measures to decrease the failure risk of the levee and suggestions to the levee operation management in flood seasons were proposed. The analytical approach and the results will be practical and helpful in levee engineering practice.

Abstract：Based on the shear tests of artificial rock joints under different shear deformation histories，the shear properties of rock joints are analyzed. The test results show that the peak and residual shear stresses increase linearly with the increase of different normal stress histories. Different shear displacement histories mainly affect the shear strength of joints，and have a little relationship with the dilatancy property of rock.

Abstract：With the thermal infrared(TIR) imaging technology，the non-contact transient process of marble rock normally impacted by a steel projectile was detected. Based on the information extraction of thermal infrared characteristics(i. e.，radiant characteristics and geometric features) from the target thermography (that just reflects part of IR radiation on the impact region，the relationships between impact-related parameters and IR-related quantities are regressively analyzed. Finally，in an additional trial，some impact-related parameters are back analyzed，such as the projectile¢s impacting velocity and kinetic energy. It was discovered that：(1) there exists a critical velocity for rock target thermography to be regular and centrally symmetrical. Within the critical velocity，the velocity of the projectile is linearly correlated to the perimeter and is quadratically correlated to the increment of TIR temperature of the target thermography；while the kinetic energy of the projectile is linearly correlated to both the area and the increment of the TIR radiant flux within the target thermography；and (2) for the quantitative back analysis to the impact-related parameters，both geometric features and radiant characteristics can be applied. It was suggested that the perimeter and the increment of the TIR radiant flux of the target thermography can be taken as the most efficient indices with the relative error of back analysis being less than 5%，while the area and the increment of TIR temperature can be taken as other auxiliary indices with error less than 15%. The results are of general meaning to the impact of other rock and solid materials；and it might extend the application of infrared remote sensing technology from static geosciences domain to dynamic mechanical domain.

Abstract：In order to ensure the security of the construction of Longshan two-arcade twin tunnel which has large span，shallow depth and bad wall rock condition，the extensive measurement and reasonable prediction of the displacements of the wall rock are necessary. After the multi-step finite element model，which can simulate the real construction process is established，the measured displacements caused by the first construction step are used in back analysis to achieve the needed parameters；and prediction of the displacements resulted from the second construction step is made based on these parameters. When the second construction step is accomplished，newly measured displacements are compared with the calculated ones. Then newly measured displacements are fed back to the established finite element model and another back analysis is taken to get the parameters which can represent the influence of these reasons of considerable differences. The prediction of displacements caused by the third step is then made based on the computed parameters. The same process is repeated until the construction is completed. It is shown from the results that if the construction state is ignored，considerable difference will occur between predicted displacements and measured ones. On the contrary，if the computation model can simulate the real construction process and the construction state，the results are encouraging. The construction state can be represented by some special parameters；and these parameters can be gotten from back analysis. Therefore，the dynamic method applied to the presentation is an effective way to predict reasonable displacements caused by construction.

Abstract：Prediction of ground movements and their surface effects is an important problem of the rock mass mechanics in the excavation activities，especially the ore mining in soft rock mining areas. Whether planned or accidental，such movements can cause considerable damage to structures located within the area of influence of underground mining works. Example is the recent subsidences that took place at the end of the 1990s in the Luzhong mining areas. A better understanding is necessary on how ground surface movements can be imparted to the supported structure and damages it. Based on the results of the statistical analysis of a large amount of measured data in mining engineering，the fundamental theoretical model of ground surface movements due to underground mining is established by using the theory of probability. The formulas of rock mass displacements and deformations are developed and applied to the prediction of the ground surface movements due to underground mining. The agreement of the theoretical results with the field measurements shows that the proposed model is satisfactory and the formulae obtained are valid；and thus can be effectively used for analyzing and predicting the ground surface movements due to underground mining in soft rock mining areas. The results show that the area of rock mass displacements and deformations in overlying strata will deteriorate with the increase in depth. The results can be used for safety assessment of shaft and the towers.

Abstract：The horizontal section top coal caving in steep seam is different from the gently inclined seam. Following the horizon of the coal seam thickness，the working face is arranged with short length. However，no roof but top coal and rock residues is found above the working face. The study shows that arch structure of spanning strata which parallels to its spanning coal seam，is formed above the working face in mining. The mechanical model of arch of spanning strata is established；and the inner forces calculation of arch，establishment of maximal arch span and arch shape are analyzed. The instability of arch of spanning strata can be cataloged as sliding instability and structure instability. The influence of instability on strata behavior of working face is analyzed and tested by field experiments. It shows that the analytical results of the proposed mechanical model agree well with those of in-situ tests measurement. The results indicate that the height of horizontal subsection can be increased. It is much meaningful to effectively control strata and to realize high yield and high efficiency for mining in the condition of short working face in steep seam.

Abstract：The dynamic response of bolt achieved by impact-echo method can be effected easily by some factors. It¢s difficult to classify bolt¢s anchoring quality according to the dynamic response of bolt. In this paper，a new analytical method of bolt¢s dynamic response is put forward. The new analytical method combing with advantages of wavelet analysis and artificial neural network is presented. Firstly，the dynamic response of bolt by numerical simulation software FLAC3D is obtained. Secondly，the features are extracted from the dynamic response of bolt by wavelet analysis. Thirdly，these features are fed into the artificial neural network for training. Finally，this artificial neural network to classify the bolt¢s anchoring quality intelligent according to the dynamic response of bolt is employed. In order to validate this new analytical method，some practical signals of bolt¢s dynamic response are used for the test. The results indicate that the new analytical method is practicable.

Abstract：Because of weak strength of soft interlayers，it is noted that rock dynamic stability caused by soft interlayers should be calculated and analyzed. However，dynamic stability analyses have been performed based on numerical simulation，but not on analytical algorithm ever before. Even if there are a few analytical methodologies，most of them are mainly used for SH wave propagating in hierarchical layers. Generally speaking，the thickness of the soft interlayer is much smaller than that of its surrounding layers；and it is shorter than the seismic wavelength. So its dynamic response model would be a scattering model rather than a direct transmission model. It is obviously reasonable that the interbedded reflecting waves should be considered. On the basis of this idea，the dynamic response model for the thin soft interlayer is put forward，which is used for a corresponding computational example.

Abstract：Based on the principle of composite element method，a new algorithm for the three-dimensional seepage problem in discontinuous rock masses is presented. The three leading features of this algorithm are as follows：(1) discontinuities segments such as faults and joints are contained in the composite elements，thus the mesh generation of discontinuous rock masses will not be restricted by the number，position and orientation of the discontinuities and can be considerably simplified. The quantity of mesh can be easily controlled；and the shape of mesh can be improved correspondingly；(2) being dissected by the discontinuities，the composite elements may contain sub-elements of arbitrary shape. The hydraulic potential in sub-elements are interpolated from their corresponding mapping nodal hydraulic potential，respectively. With the solved mapping nodal hydraulic potential，the velocity，flow rate in each sub-element can be calculated；and those in discontinuities segments are calculated from the two sets of mapping nodal hydraulic potential of their neighboring sub-elements；(3) in composite element method，the solving procedure of the mapping nodal hydraulic potential is similar to that in conventional finite element method，and the elements containing no discontinuities are degenerated to conventional finite elements automatically. Thus the programs for composite element algorithm can be incorporated into the conventional finite element analysis procedure with intrinsic coherence. The comparative study between the composite element method and the conventional finite element method for seepage problem has been implemented with two simple models and a gravity dam example，respectively；and the validity and effectiveness of this new algorithm are verified by the given examples.

Abstract：Accurate classification of surrounding rock mass is not only an essential problem for the highway tunnel¢s design and construction，but also a guidance to pre-forecasting the geology of surrounding rock mass precisely. It can provide considerable theoretical application and significance for the tunnel¢s construction and safety maintenance. In the current specification codes for the classification of surrounding rock mass in highway tunnel，corresponding specific connection between categories and evaluation indicators of surrounding rock mass is not established yet. In addition，actual application of the current codes is often affected by subjective factors. Aiming at the existing fuzzy problem in the current specification codes，firstly，a good deal of data pertinent to the classification of surrounding rock mass have been collected，analyzed and summarized，showing that quantitative classification of surrounding rock mass represents the international trend. Secondly，the concept of fuzzy information analysis model is brought forward here to deal with the fuzzy problem in the current specification codes by virtue of abundant information from actual examples. Then，expert system of fuzzy information for the classification of surrounding rock mass in highway tunnel is presented according to fuzzy mathematics theory and the current specification codes for the classification of surrounding rock mass in highway tunnel，which will make progress in quantitative classification of surrounding rock mass. Finally，the above new theory is applied to surrounding rock mass classification of highway Manxie tunnel No.3.

Abstract：It is important to grasp the process of landslide translation to debris flow on the basis of the experiment of landslide translation to debris flow. Four artificial rainfall experiments have been carried out at Wanfangzi，located in the debris flow source area of Jiangjia Ravine，and other four experiments have been performed at the deposit area. The Jiangjia Ravine is a famous debris flow gully. After investigating whole drainage area，the conditions and locations of these experiments are determined. In the process of these experiments，some soil parameters have been measured through some advanced equipments. These parameters are water potential，water content，pore water pressure and soil temperature. After primary analysis have been completed，some basic characteristics of wide-graded gravel soil are presented. Main conclusions include：(1) under the strong-intense rainfall，the mechanism of landslide translation to debris flow is the vibration softening or the vibration liquefaction，and the soil strength can be expressed by the function of grain grade，saturation，and pore water pressure induced by the vibration and infiltration rate；(2) when soil is broken，the soil may be unsaturated，so the mechanism of saturation liquefaction has not been applied；(3) when the curve of water potential declines，the process of soil strength fluctuation will be validated；(4) the energy exchange exists in the process of soil break；and (5) under the strong-intensity rainfall，it is difficult to distinguish the start of landslide against the formation of debris flow，because the characteristics of debris flow appear when soil is broke.

Abstract：The bond prestressed anchor ropes have been used in slope engineering，however，the mechanism of load transfer of bond section is not clearly seen. In this paper，the behavior of bond prestressed anchor rope is investigated based on the shear stress-slip relation of interface between bond body and surrounding rock and shear lag model. Both the length and shear distribution of bond body are determined. Through a case of study，the validity of proposed method is verified by comparing the predicted results with existing experimental data.

Abstract：Considering the true construction process of Pengshui Hydropower Station roller compacted concrete(RCC) gravity dam and adopting the blunt crack band model of concrete，transient finite element is applied to simulating layer-by-layer construction process to get the temperature field and stress field from construction period to operating period. Then crack and propagation of the dam-induced slits are computed by dynamic tracking method. The simulating analytical results of the whole dam show if induced of slit tip stress intensity factors exceed tensile bearing capacity of concrete on upstream face，and induced crack occurs. The crack of induced slit leads to tensile stress release near slit. The length of the induced slit of Pengshui Hydropower Station dam is suggested to 4.5 m on the basis of the cracking analytical result.

Abstract：In water-conveying tunnel of permanent shiplock of Three Gorges Project，some cracks are found in early phase cast concrete lining. These cracks，existing in the middle of a tunnel section，and transverse direction，seriously effect the quality and life span. So，field experiment on concrete lining temperature field of tunnel sections NY9 and NY10 of north extension，where temperature-controlled concrete and no special temperature controlled concrete are cast，respectively，is conducted. Experimental results show：(1) the highest temperature of lining caused by hydration heat can reach above 50 ℃；and (2) both the temperature rise and the temperature drop are quickly. The concrete lining temperature begins to drop within 3 days with large drop scope. Because of the thin structure and strong constraint of surrounding rock，lower tensile strength of concrete，etc.，early stage cracks occurred. The reason that cracks are developed during construction periods is analysed；and the importance of temperature controlling to prevent cracks in tunnel lining during construction periods is pointed out. Some feasible measures and proposals are put forward. These measures and proposals，adopted by construction units are proved to be effective and economical.

Abstract：Based on a case of crush rock slope K81 in Jinhua－Lishui－Wenzhou Highway，an analytical mechanical model was developed. According to field testing data，the compression deformation and subsidiary stresses of the crush rock slope under prestressed cables anchorage forces were analyzed by numerical simulation. The results are shown as follows：(1) it is suggested that light-tonnage cables should be employed in crush rock slope reinforcing engineering in consideration of low deformation modulus of the slope. The tensile force of 500–750 kN can be adopted；(2) the range interval of the cables should not be too small for the reduction of adjacent cable stretch-draw influence. On the other hand，the interval should not be too large to avoid subsidiary stresses looseness. The proper interval between cables in crush rock slope should be 4–6 m.

Abstract：The meshless manifold method is utilized to analyze transient deformations of the elastodynamics，especially，with discontinuity in the solving domain. The shape function is built with the method by the partition of unity and the finite cover technology，so the shape function cannot be effected by discontinuity in the domain to treat continuous and discontinuous dynamics problem easily. To local problems，the shape functions are built more effectively than other method. So the method can avoid the disadvantages in other meshless methods in which the tip of the discontinuous crack isn¢t considered. The approximation functions will not be influenced by the discontinuity in the solving domain if finite cover technology is employed in the method，which can overcome some difficulties when the problems are solved with the meshless methods. When the meshless manifold method is utilized to analyze the elastodynamics，the method is divided into the major two parts：the discrete space of the domain is used to the partition of unity，which the present method void to mesh element and refine element. So the method has good continuity in the area of the computing stress for element-free of the analysis problem. The Newmark methods is used for the time integration scheme. The scheme is a widely direct integration method. The local weak formulation of the dynamic partial differential equation for elastic is derived from the method of weighted residuals(MWR). At last，the validity and accuracy of the presented meshless manifold method solution are illustrated by the 2D plate of the elastodynamics. The meshless manifold method results show that the stresses and the displacements at the critical point agree well with those obtained from the analytical solution.

Abstract：A common area of construction berm in subgrade project was considered based on the mechanical stability of slope. When Qinghai—Tibet highway is rebuilt，some sections of the highway construction berm to obstruct seeper in slope angle are adopted；and the berm could be used for heat preservation. Aiming to study the berm¢s effects of ground temperature characteristics of embankment on permafrost，numerical modeling was used to calculate the temperature field，according to the characteristic of the highway，comparative analysis and the research of the laws. It shows that construction berm has limit effect on the ground temperature characteristics of embankment such as artificial permafrost table，annual mean ground temperature and thaw bowl，however，the thaw depth well increase and annual mean ground temperature will rise. High temperature on permafrost berm could deteriorate the degeneration of the frozen soil under the embankment. The result indicates embankment berm on permafrost region should not be regarded as the main measure to improve thermal stability of embankment.

Abstract：Xinguang bridge project is the pivotal project of Xinguang throughway，and it will be the longest half-through arch bridge with three continuous spans in the world. The constructions of piers No.5 and No.6 meet much difficulty in this project due to the large-span，deep water，and intricate geologic conditions as well as water inpouring into hardpan in their sits. On account of all those factors，cofferdam with steel sheet pile is employed in this project with large dimensions，which is the largest steel sheet pile cofferdam in deep water in Guangdong Province. However，successful implementation of this project lies in how to solve the permeating problems of steel sheet pile cofferdam. As to the permeability problem，the formula for the equivalent permeability coefficients is modified. On basis of this modified formula，a variety of the equivalent permeability coefficients is modified during the self-healing up process of the steel sheet pile in the sandy layer are analyzed；and the calculation of the final seepage quantity as well as an estimation of the initial quantity of the pumped water are presented Moreover，it is concluded that permeability below the root of steel sheet pile will not cause seepage failure but only increase the leakage，which is confirmed by the two-dimensions finite element program on horizontal plane. Eventually，corresponding settlement was generated after a full account of both the merits and demerits of the cofferdam base in both draining and blocking up approaches. This project was completed smoothly，and complementary supporting evidences of the self-healing process of the steel sheet pile were deduced.

Abstract：Because of continuous precipitation and cracked surrounding rock，collapse of tunnel was found in the section YK73+955–YK73+925. According to engineering geology and in-situ construction condition，ahead ductile grouting method was applied to the surrounding rock consolidation of the tunnel. In order to investigate consolidation effect，two cross-sections of collapse zone measurement were increased；and finite element simulation analysis was applied to a cross-section. Measurement and calculation results of convergence displacement and vault subsidence show that tunneling collapse zone was consolidated by ahead ductile grouting method successfully.

Abstract：The evaluation of drillability anisotropy of the formation is very important for well trajectory control. The velocities of ultrasonic wave and rock drillability are measured in perpendicular and parallel directions of the bedding plane of core samples which were cut from the approach hole of Chinese continental scientific drilling. Rock drillability index and P-wave velocity anisotropy coefficient are calculated from the testing data；and the results are discussed. Correlation of drillability anisotropy index of the roller cone bit and PDC bit，the difference between drillability of the roller cone bit in perpendicular and horizontal directions of the bedding plane with the P-wave velocity anisotropy coefficient are studied respectively by means of mathematical statistics. A mathematical model is established for predicting drillability anisotropy index by using P-wave velocity anisotropy coefficient. Thus，drillability anisotropy of a formation can be evaluated conveniently from seismic or logging data by using this model. The method is used to evaluate drillability anisotropy of a formation of Well AN2004 in Henan Oilfield in China. The result shows that the formation drillability anisotropy index predicted by using this method can properly reflect the deviation characteristics of the formation being evaluated.

Abstract：Tensile strength is one of the most important mechanical properties of rock for design of subterranean engineering constructions. It is also a key parameter of rock for strength design，safety and stability analysis of rock structures. The Brazilian test is an essential method for testing tensile strength of rock，which is widely used in the geotechnical engineering and rock mechanics. There is a great difference，however，in the testing results of tensile strength due to different contact conditions. Numerical calculation of FEM and experimental investigations are used in the present research. The influence of loading condition and size of indenter on the tensile strength of rock has been investigated. The results obtained by numerical calculation and experiments show that tensile strength of rock will increase with the increase of indenter size. The difference of tensile strength produced by testing and numerical calculation will decrease when using smaller contact angle or indenter diameter. Experimental results obtained with white marble specimen show that a stable tensile strength with higher precision can be achieved when the ratio of d/D is in the range of 0.024–0.040. It gives a reference to choosing reasonable size of indenter in Brazilian test. This method provides theoretical and experimental basis for testing tensile strength of rock accurately.

Abstract：The retaining system of a foundation pit is a temporary structure. Retaining piles and continuous concrete walls have been widely used for simpler bearing mechanism with higher excavation efficiency and lower cost. Especially，they have been used for spacious foundation pit with complicated shapes. However，it is reported that 43.86 percent of the foundation pit were caused by improper design method，unstable bracing system and ignoring stability analysis of foundation pits. Accordingly，optimum design of a foundation pit and the bracing system is an efficient method to avoid the pit failure and reduce project cost. As an example，a deep foundation pit has been analyzed by means of elastoplastic finite element method. Stability analysis of the pit is performed with changing the positions of the braces. More attentions have been paid to the deformation and stress of the retaining structure and strength in the braces. Analytical results show that the bracing position change may bring little effect on stress ratio in soils，but great effect on the position and value of the maximum displacement in the retaining wall. The maximum bending moment in the retaining wall will change with the bracing position. The axial force in the brace is sensitive to the bracing position. When the second brace is moved upwards，the axial force in the first layer decreases and the force in the third layer increases with a ratio of 11%/m. While the second brace is moved upwards，the axial force in both the second brace and the third brace decreases slowly with a ratio of 4%/m and 5%/m，respectively；and the axial force in the first brace is keeping increasing by a ratio of 30%/m.

Abstract：This paper takes the advantages of the scientific substances of the different rock classification methods and studies the characteristic of the sample distribution according to the different classification methods. With the sample distribution characteristic which increases the dependability of the classification，the statistics regulation and the synthetic regulation coordination were studied. According to the condition of Pingdingshan mining area，the overall classification for rock¢s stability was proposed on the basis of the three indices of the ground pressure coefficient，the loosen area，and the joint propagation¢s degree. The classification figure expresses the sample¢s distribution regulation. It increases classification dependability，and simplifies the classification method. The statistical criterion for appraising rock stability was obtained by studying the coal roadways in Pingdingshan mining area. A new kind of stability overall classification method was put forward. Based on roadway condition and measured information，the stability was evaluated and the multi-index rock classification figure was presented.

Abstract：Based on the design and construction of Xicun Station，the fifth line of Guangzhou metro，this paper demonstrates the stressing characteristics and displacing law of existed pile foundation project in the process of station tunnel construction with finite discrete method(FDM) and puts forward the key construction process，effective reinforcement method. The study shows that friction of pile lining presents negative friction，and negative friction severely affects the bearing capacity of the pile；maximal axial forces of fly-over crossing pile increase 30% with maximal bending moments increasing 2 times. The coefficient of safety reduces 40%；and the bearing capacity reduces 40% correspondingly. Therefore，attention to the key process of construction is necessary；fly-over crossing pile belongs to supported pile，and bearing capacity of pile end is insufficient，therefore，corresponding strengthening measures should be taken. Inner forces of footbridge pile are seldom varied；but displacement changes a lot. As a result，the close attention should be paid to the change of the upper structure in the process of tunnel construction；footbridge pile belongs to frictional pile，and the friction force of pile lining is less than the calculated friction force. In addition，homologous reinforcement measurement should be taken.

Abstract：Yuanliangshan tunnel，with a total length of 11.068 km，is the longest tunnel on Chongqing—Huaihua railway. The tunnel goes mainly through the core of Maoba syncline core，Tongmaling anticline and Lengshuihe shallow-buried section，where the Maoba syncline，Tongmaling anticline and ruptured zones develop. Because of the influences on the geological structures，there exist two layers of artesian water of P2w+c and P1q+m. The deep-hole drilling exploration shows that the pressure of the artesian water reaches up to 4.42–4.60 MPa. On the basis of the exploration data and the surrounding environment，it is estimated that the normal water inflow of the complete tunnel reaches 98 000 m3/d with the maximum water inflow of 145 000 m3/d. During the construction of Yuanliangshan tunnel，5 karst caves have been encountered in Tongmaling anticline and Maoba syncline，which have different shapes and different filling materials such as fine silty sand，silty clay and clay. Among them，the karst cave No.2 is the most difficult for it is filled silty fine sand layers. Due to the influence of the high pressure，rich water and karst geology，several large-scaled sudden water inflows，sand inflows and mud inflows are encountered，which have imposed serious influences on the safe and successful constructions of the tunnel. By means of silty fine sand layers，the paper researches the grouting systems that consists of cement single liquid grouting material，MC super and thin cement single liquid grouting materials，cement and water glass of liquid grouting materials，MC super and thin cement and water glass of liquid grouting materials，TGRM single liquid grouting material，and HSC single liquid grouting material，respectively. The grouting design，grouting parameter，grouting result check of the karst cave No.2 and two passive countermarch returns to fill the situation are analyzed，which can provide an important reference for future tunnels under similar geological conditions.

Abstract：Based on the medium-sized triaxial test and the large-scale field direct shear test，the strength properties of coal wastes from Xuzhou in China，are systematically studied. The results show that the strength of coal wastes can be described by Coulomb¢s equation or De Mello equation for shear strength. The parameters for these formula are presented. When the coarse grain(D＞5.0 mm) proportion in samples changes from 30% to 60%，the shear strength is seen with obvious changes differently with the pure coarse or fine samples. The influential factors on the coarse crush are also compared，in which the confining pressure and the coarse grain content are the primary factors. In the end of the paper，it is indicated that the cohesion of coal waste from the field shear test is smaller than that from laboratory test；while the friction angle from the field test is larger than that from the laboratory test. The mechanism for above results is achieved.

Abstract：The compaction tests of earth-rock mixture with different gradations，coarse material contents and fragmentation ratios，are performed；and the influence of compaction effectiveness，compaction methods and equivalent treatment methods on earth-rock mixture compaction result are analyzed. The results indicate：(1) the good gradation sample has good compaction property；(2) when coarse material content exceeds 75%，the largest dry density almost remains the same；and the compaction work should not too strong；and (3) the results of equivalent replacement method is close to those of large-scale compaction test. In order to get a better compaction result，the above-mentioned factors are analyzed comprehensively.

Abstract：Investigation on negative skin friction(NSF) is complicated in the effort to connect with some other theoretical problems in soil mechanics field. Consequently，it could help to advance our understanding on these problems in soil mechanics field in the NSF. However，some theoretical problems of the NSF are not interpreted reasonably. In order to understand the problems three important theoretical problems of the NSF：the dominant influencing factors of the NSF，the relation between NSF，and weight of the soil mass around pile and the power sources of the NSF are analyzed. Based on the in-situ data and theoretical analysis，two dominating factors，i.e.，the effective weight of the soil mass above certain depth and the settlement of the soil mass around the pile at the certain depth，are discussed. Then on the basis of the two above-mentioned dominating factors，the NSF could be regarded as a force acted on pile due to the lost gravitational potential energy of the subsiding soil mass，and as the force limited by shear strength of the soil mass. Finally，a theoretical model of power sources of NSF to illuminate the results is established.