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2003, 22 (02): -0 doi:
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ESTIMATING THE DYNAMIC STRENGTH OF ROCK USING MOHR- COULOMB AND HOEK-BROWN CRITERIA

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2003, 22 (02): -171 doi:
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A series of dynamic compression，tension and shear tests were conducted on the Bukit Timah granite of Singapore. The results are analyzed in an effort to examine the validity and the applicability of the Hoek-Brown and Mohr-Coulomb criteria for rock material under dynamic compression. It is indicated that the rock strength can be approximately described by the Mohr-Coulomb criterion at low confining pressure. The change of strength with loading rate is primarily due to the variation of cohesion with loading rate. The dynamic compression strengths are more accorded with the Hoek-Brown criterion，especially under higher confining pressure(higher than 100 MPa).

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PHYSICAL MECHANISM OF DEPENDENCE OF MATERIAL STRENGTH ON STRAIN RATE FOR ROCK-LIKE MATERIAL

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2003, 22 (02): -177 doi:
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In the past，the dependence of dynamical strength of brittle materials like rock on strain rate was studied mainly experimentally，and the theoretical aspects，especially the physical mechanism from low strain rate to high strain rate are not studied systematically. Based on available research results，the physical mechanism of strength-strain rate sensitivity in different strain rate regions and the transition between them are studied. The study result shows that in small strain rate region，strength-strain rate sensitivity is controlled by thermoactivational mechanism. With the increasing of strain rate，the macro-viscosity mechanism arises，and gradually becomes dominant. In high strain rate region，inertia effect becomes very significant，and the growth of defects of a wide range of sizes will be initiated simultaneously，and then the thermoactivational rupture of atomic bonds will take place in the area without defects. Thus the strength-strain rate sensitivity can be considered as the result of competition between the coexisting thermoactivation mechanism and the macro-viscosity mechanism，which plays dominant roles in different strain rate regions. On this basis，a unified model of competition between thermoactivational mechanism and the macro-viscosity mechanism is given，and the effectiveness of the model is verified with experiment data and good accordance is obtained with the experiment data.

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ANALYSIS ON MICRO AND MESO-DAMAGE OF ROCK BY MACRO-HYSTERESIS CURVE

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2003, 22 (02): -182 doi:
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The cycle loading experiment is conducted on MTS with frequency of 5～15 Hz and stress beyond the yield strength of sandstone. By studying the variation of shape and area of s -e hysteresis curve and the variation of volume strain with axial strain，the evolvement of micro-damage of rock，the variation of axial strain and the strain hardening and softening under cycle loading condition are discussed.

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SIZE EFFECT ANALYSIS ON STRAIN SOFTENING OF QUASI-BRITTLE MATERIALS CONSIDERING STRAIN GRADIENT EFFECT

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2003, 22 (02): -188 doi:
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The effect of length due to shear localization is studied. Based on non-local theory considering interaction among microstructures，non-local plastic shear strain is obtained，and dependent on local plastic shear strain and its second spatial gradient. For simplicity，shear band is treated as one-dimensional problem and the closed-form solution on plastic shear strain in shear band is obtained. Then，an analytical relation between axial average strain (or displacement) and axial compressive stress is obtained，which exhibits size effect. The relation becomes steep as length is increased and class II behavior can occur as length is large. Besides，the relation also becomes steep as inclination angle of shear band increases. The presented theoretical results are compared with a few existing experimental results and the agreement is good.

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NEW EVOLUTIONARY BACK ANALYSIS ALGORITHM
IN GEOTECHNICAL ENGINEERING

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2003, 22 (02): -192 doi:
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Through analyzing the shortcoming of the traditional optimization back analysis in geotechnical engineering，the suitability of the evolutionary back analysis is proposed. Also，the weakness of the genetic back analysis is revealed. In order to overcome the defect of those optimization methods，a new algorithm——immunized evolutionary programming (IEP) based on the traditional evolutionary programming (EP) and the principles of immunized artificial system (IAS) is suggested here at first time. Combining IEP with FEM，a new back analysis algorithm——IEP back analysis is proposed. Through a simple example，the proposed algorithm is verified，and the results show that this new algorithm is very good and available for practical application.

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COMPARISON STUDY OF MIXED OPTIMAL METHODS BASED ON GENETIC ALGORITHM IN BACK ANALYSIS

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2003, 22 (02): -197 doi:
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In light of computing speed，precision and reliability，the following three problems related to traditional and modern optimal methods are mainly studied： (1) the mixed genetic algorithm is presented based on the idea of coupling genetic algorithm with damping least square technique；(2) the above mixed genetic algorithm and simulated annealing-genetic algorithm are led into back analysis in geotechnical engineering early；(3) some optimal methods，such as the simplex method，damped least square technique，genetic algorithm，simulated annealing-genetic algorithm and the mixed genetic algorithm，are evaluated and compared. The studied results show that compared with the traditional optimal methods like the simplex，the modern one based on genetic algorithm is of better convergence in whole region，and compared with the common genetic algorithm，the mixed genetic algorithm and simulated annealing-genetic algorithm effectively improve searching speed，precision and reliability of genetic algorithm.

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BACK ANALYSIS OF 3D SEEPAGE PROBLEM AND
ITS ENGINEERING APPLICATION

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2003, 22 (02): -203 doi:
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A new method is proposed for the back analysis of 3D seepage problem. The variables of back analysis are determined firstly，and then the utilization of the sequential quadratic programming and high-efficient sensitivity analysis is suggested to promote the computation efficiency. The convergence of this method is very good. As an engineering example，the seepage field of Tai’an pumped-storage power station is back analyzed. In comparison with the observed values，the back analyzed results are reliable and the accuracy meets the engineering demands.

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INTELLIGENT RECOGNITION METHOD OF DEEP
FORMATION PORE-PRESSURE

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2003, 22 (02): -208 doi:
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[PDF 176 KB] (912)

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Deep formation pore-pressure assessment is very important for evaluation and exploitation in oil and gas fields. Aimed at the deficiency of the present formation pressure assess methods，the evolvement characters of formation pressure time-series is analyzed at first，and then a method is proposed to build the neural network intelligent recognition model. A formation pressure intelligent recognition software is developed based on the MATLAB neural network toolbox. This software is proved to satisfy the engineering needs when used to evaluate the actual formation pore-pressure of well of Q002 in Talimu oil field. In this practice，the recognition average error is 4.02% to normal sediment stratums，and 6.57% to non-normal sediment stratums. This method is simple，efficient，intelligent and can be used to evaluate formation pore-pressure in advance.

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FLOW FIELD SIMULATION OF CRACKING PATH FOR ROCK-TYPE MATERIALS UNDER COMPRESSIVE LOADING

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2003, 22 (02): -212 doi:
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Based on the principle of correspondence between velocity field of incompressible viscous fluid in steady state and displacement field of incompressible elastic solid in equilibrious state，the stress formulae expressed in stream function are deduced and the equivalent relation between streamline and principal stress trajectory is derived. Using the solution of streamlines of the flat-plate flow，the extension law of cracking path for rock-type materials is predicted under compressive loading，which is in good consistence with the experimental results.

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TRANSFORMATION OF STRESS SPACE ——
NEW PATH FOR CONSTITUTIVE DESCRIPTION OF GEOMATERIALS

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2003, 22 (02): -217 doi:
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The allowable stress state of geomaterials is limited by critical state line. The plastic deviatoric deformation becomes larger and larger and geomaterials tend towards to damage，when the stress state of geomaterials is close to the critical state line. The opposite phenomenon appears when the stress state of geomaterials departs from the critical state line. This is one phenomenon of stress-induced anisotropy. Based on the anisotropy induced by the critical state line，the idea of transformation of stress space is presented. With reconstituted soils taken as an example，the formulas of transformation of stress space and stress increment are provided，and the influence of stress Lode’s angle is considered also. A new path is provided for constitutive description of geomaterials by transformation of stress space. The motion of yield surface and bounding surface with isotropic hardening or kinematic hardening is limited in the allowable stress space，and the stress-induced anisotropy and the influence of stress path can be considered reasonably in the transformed stress space.

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STUDY ON DAMAGE EVOLUTION OF CONCRETE
UNDER IMPACT LOAD

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2003, 22 (02): -223 doi:
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A new method which could be called‘freezing in’test of damage in concrete is carried out on SHPB test system. Compared with the quasi-static test data obtained with the MTS test system，the results from SHPB test system show that the damage evolution is of close correlation with the value of strain and strain-rate. Using a fitting program，the equation of damage evolution of concrete is obtained under impact load.

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APPLICATION OF ROSENBLUETH MOMENT ESTIMATION METHOD
INTO PROBABILISTIC ANALYSIS OF SLOPE STABILITY

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2003, 22 (02): -232 doi:
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The basic principle of Rosenblueth moment estimation method and its application into probabilistic analysis of slope stability are presented. The safety factor，reliability index and failure probability are given with this method. This method can combine the conventional safety factor with probabilistic analysis. A dual index system is setup to assess slope stability with safety factor and reliability index. As an example，the stability of Yancun landslide is assessed，and the results are tallied well with the practical case of the landslide.

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COUPLING CONSTITUTIVE RELATION BETWEEN AE PARAMETER AND STRESS-STRAIN AND ITS APPLICATION

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2003, 22 (02): -232 doi:
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Acoustic emission (AE) is one of the important information in detecting and analyzing reliability of concrete structure. As stress and strain，so AE is also a constitutive parameter. The coupling relation between AE and stress-strain can be expressed in constitutive function. The characteristics of the un-reversibility of AE-process can be used to determine the loading history and the highest load used to act on a structure. Therefore，AE monitoring can be used to detect and analyze the reliability of concrete structure.

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GLOBAL SEARCH ALGORITHM OF MINIMUM SAFETY FACTOR FOR SLOPE STABILITY ANALYSIS BASED ON ANNEALING SIMULATION

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2003, 22 (02): -236 doi:
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[PDF 203 KB] (1940)

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Based on the modified annealing simulation and simplified Bishop method for computing slope stability，an effective global minimization algorithm is presented for searching the minimal safety factor. The algorithm can simultaneously determine the minimal safety factor and the corresponding slip surface，and be applied to slopes with any geometry，layering，pore pressure and external load distribution. The application of the algorithm to slope stability problems shows that it can be used to search the global minimal safety factor for slope stability analysis by getting rid of local minimization.

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APPLICATION OF SUPPORT VECTOR MACHINES FUNCTION FITTING IN SLOPE STABILITY EVALUTION

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2003, 22 (02): -241 doi:
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Different methods for evaluating slope stability are comprehensively analyzed．The method of support vector machines is proposed for evaluating slope stability and builing predicting model．Based on a large set of slope samples，practical effectiveness of the theory of support vector machines for slope safety prediction is discussed．

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APPLICATION OF PROBABILITY ANALYSIS TO IMPROVEMENT OF MEASURING PRECISION OF FRACTAL DIMENSION

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2003, 22 (02): -246 doi:
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In light of the fact that the measurement of fractal dimensions is usually inaccurate，a method for modifying the testing data based on probability analysis and statistics is proposed to reduce testing errors and improve the precision of fractal dimensions. In addition，by practical proof-tests of testing measurements，it is proven that the methodology is basically feasible.

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INTERNAL FORCE CALCULATING METHOD OF PRESTRESSED-CABLE BEAM-ON-FOUNDATION FOR HIGH ROCK SLOPE

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2003, 22 (02): -250 doi:
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The model of forces of prestressed-cable beam-on-foundation during tension and consecutive working stages is analyzed. The principal force difference between the two stages is pointed out，which results from the variation of foundation reaction. The internal force of prestressed-cable beam-on-foundation should be respectively calculated for each stage. The model of beam on half-space elastic foundation can be used on the first stage and the model of continuous beam can be directly used on the next stage. The main calculation procedure is given by a practical project.

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STABILITY ANALYSIS ON JOINTED ROCK SLOPE BY STRENGTH REDUCTION FEM

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2003, 22 (02): -254 doi:
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Stability analysis is made on the jointed rock slope by nonlinear FEM strength reduction method. With the c-j reduction，the nonlinear FEM model of jointed rock slope reaches instability and the numerical non-convergence occurs simultaneously. The safety factor is then obtained by c-j reduction algorithm. At the same time the critical failure surface and overall failure progress are found automatically. This presents a new approach for jointed rock slope stability analysis as the traditional limit equilibrium method can't get the safety factor and failure surface of jointed rock slope. Through a series of case studies，the applicability of the proposed method is clearly exhibited.

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ON BASIC WAY TO DRAMATICALLY INCREASE THE BEARING CAPACITY OF UNDERGROUND ENGINEERING IN ROCK MASS

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2003, 22 (02): -261 doi:
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By qualitative mechanics analysis，model tests，dynamic loading tests，and numerical calculation and analysis，it is showed that the stress transmission in stratum is closely related to the relative stiffness of the medium，and a new concept——the concept of stress transmission is proposed. If the new concept is effectively applied to the construction of protective and underground stuctures，the bearing capacity of the structures could be dramatically increased.

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DISPLACEMENT-BASED METHOD FOR RELIABILITY ANALYSIS OF
SHOTCRETE LINING OF TUNNEL

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2003, 22 (02): -266 doi:
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[PDF 166 KB] (1272)

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In the dynamic design of tunnel constructed with the New Australian Tunnelling Method，it is important to calculate the reliability of the lining structure by in-situ measurement data of displacements. Following the investigation of variability of random variables including lining displacement，thickness of shotcrete and properties of shotcrete material，the performance functions for section failure are put forward. Two case studies are conducted by using Monte-Carlo simulation to check the rationality and correctness of the proposed method.

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DESIGN METHOD OF BOLT SUPPORT FOR COAL SEAM ROADWAY BASED ON GEOSTRESS

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2003, 22 (02): -270 doi:
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[PDF 266 KB] (1080)

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A dynamic bolt support design method for coal seam roadway is reported. The method includes the steps of geostress test，geomechanics evaluation，initial design，in-situ measurement，information feedback and design revision. Other methods like numerical stimulation，in-situ test and monitoring，and engineering analogy are also used to optimize the design.

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RESEARCH ON LATERAL PRESSURE IN TRUSS ROD
FOR SUPPORT OF LOOSE ROOF

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2003, 22 (02): -276 doi:
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The lateral pressure acting on rod is studied through physical simulation tests in the condition of loosed roof supported by truss rod. The lateral displacement and pressure of rod are analyzed according to test results and elastic foundation beam theory. The rod model is built based on rope theory. The deformation trajectory equation and tensile force of rod are obtained.

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EFFECT OF BLAST IN DOUBLE LINE TUNNEL
ON EXISTING TUNNEL

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2003, 22 (02): -281 doi:
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[PDF 332 KB] (1316)

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In general，as the distance between double line tunnel and existing tunnel is very small，excavating blast in double line tunnel will affect structure safety of existing tunnel. The effect factor of excavating blast in double line tunnel on existing tunnel is first analyzed. In addition，the finite element method is applied to analyze the effect of blast vibration，and excavating blast in Guanzhai double line tunnel is taken as an example. The results show that finite element method can fully describe the whole process of blast vibration.

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DYNAMIC PROPERTY ANALYSIS ON JOINT FOR SUBMERGED
TUNNEL UNDER EARTHQUAKE

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2003, 22 (02): -286 doi:
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Based on the mathematical model for analyzing the earthquake response of submerged tunnel，the analytical model for the Nanjing Changjiang Tunnel is proposed. The comparative calculation of dynamic property of the tunnel joint is completed under the condition of rigid joint，hinged joint，elastic joint and so on. It is shown that the change of dynamic modulus of elasticity and modulus of resistance of ground may affect the dynamic property of the tunnel joint.

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CONSTRUCTION TECHNIQUE OF LARGE-SPAN TUNNEL UNDER CONDITION OF COMPLICATED SURROUNDING ROCKS

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2003, 22 (02): -290 doi:
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Based on some triple-line large-span tunnels under complicated geological condition in Neijiang－Kunming railway，the theoretical analysis，numerical simulation and field survey are used to analyse surrounding rock deformation characteristics and structure stability. Consequently，rational construction methods and assistant construction methods are determinated. After comparing different construction projects，optimal initial shoring modes and parameters are proposed in practice. On the base of analyzing the stability characteristics of rock pile body，accordingly，the construction technique，proof-caving and consolidation measure are established，and satisfactory effect obtained in engineering practice.

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RHEOLOGICAL STUDY ON BOLT-GROUTING SUPPORTED
ROADWAYS IN SOFT ROCK

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2003, 22 (02): -297 doi:
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The computing models of bolt-grouting support for two-way unequal roadways in soft rocks are set up. Rock strata around roadway are divided into reinforced zone of bolt-grouting support and unreinforced zone，in which different viscoelastic models are used and the stress-displacement relationship of roadways is derived. The viscoelastic solution is reasonable compared with practical observed displacement curve of bolt-grouting supported roadways in soft rocks.

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PROPAGATION CHARACTERISTICS OF PLANE SH WAVE PASSING THROUGH ELASTIC INTERLINING IN ELASTIC MEDIUM

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2003, 22 (02): -304 doi:
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With the aid of wave propagation theory and Snell theorem，a theoretical study on propagation characteristics of plane SH wave passing through layered elastic medium is conducted. Exact solution of dynamic equation is derived．The curves, representing the relationship among reflection and transmission coefficients，medium parameters and incident angle，are obtained by numerical computation．The results show that transmission coefficients are dependent not only on medium parameters but also on interlining thickness and incident angle．

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EFFECTS OF SOIL-STRUCTURE INTERACTION ON THE RESPONSES OF STRUCTURE TO WIND-INDUCED VIBRATION

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2003, 22 (02): -309 doi:
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Through the response evaluation of frame structures to wind-induced vibration，the effects of soil-structure interaction (SSI) on the responses of the structures are illustrated. Evaluation results show that in the response analysis of structure to wind-induced vibration，the effects of SSI on the wind responses are not always conservative. SSI can obviously reduce the first resonant frequency of the structure system. When the damping in soil is small，the elastic relative displacements of structures with SSI may be greater than that of structures without SSI. This phenomenon is more significant if the relative stiffness of the superstructure and its surrounding ground is smaller. Moreover，the total displacements of the structure with SSI are always much greater than that of the structures without SSI，which can make people produce strong uncomfortable perception. Therefore，in the response analysis of structure to wind-induced vibration，the effect of soil-structure interaction should be considered.

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FINITE ELEMENT NUMERICAL SIMULATION OF DEEP FOUNDATION PIT EXCAVATION SUPPORTED BY FROZEN SOIL WALL WITH NONHOMOGENEOUS TEMPERATURE DISTRIBUTION

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2003, 22 (02): -316 doi:
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The deformation of deep foundation pit is analyzed by using the subsection approximation of finite element numerical simulation. The nonhomogeneous temperature distribution is considered by the analysis of temperature of frozen soil wall，and the results of nonhomogeneous temperature distribution are compared with these of the homogeneous ones. Many significant conclusions are obtained and some valuable advice for construction and design is given.

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TESTING STUDY ON DEFORMATION AND STRESS OF REINFORCED EARTH RETAINING WALL FOR HIGH EMBANKMENT

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2003, 22 (02): -321 doi:
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A reinforced earh retaining wall with height H = 31 m and four steps was builded in the main railway line of China firstly. In order to research the lateral deformation，basement pressure and lateral pressure of each wall，the testing study is made on the full-scale. It is disclosed that the lateral deformation of the low position is larger than that of the top position for each wall，the basement pressure of each wall is smaller than 100 kPa，and the lateral earth pressure with curve distribution is confirmed. The lateral earth pressure is constant basically for each wall because of the bench of 4 m behind wall. The test results can be used as a reference for future studies and designs of reinforced earth retaining wall.

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APPLICATION OF SEMI-ANALYTICAL SOLUTION
INTO CONSOLIDATION OF LAYERED SOFT CLAY

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2003, 22 (02): -327 doi:
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Viscosity is one of the important characters of soft clay. Due to the viscous deformation of subsoil，consolidation shows secondary time effects. Another important character of natural subsoil is layer. According to a layered soil model，the semi-analytical solution for one-dimensional consolidation of layered soft clay under time-dependent loading is presented and the computer program is developed. Based on the computing result，some useful consolidation diagrams are obtained and the relevant characters of the consolidation of layered soft clay is discussed.

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TESTING STUDY ON MECHANICAL PROPERTIES OF SLAB
ROCKFILL DAM MATERIALS

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2003, 22 (02): -332 doi:
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The dam of Yixing pumped-storage hydroplant is a slab rockfill dam. The laboratory tests were made on the relation among gradation，density and content of mudstone and the physical and mechanical properties of rockfill material. The testing results show that the maximum dry density of rockfill should be tested by the platform vibrator. The compact rockfill materials are of the properties of high permeability，low compression，low failure strain and high shear strength. The graded material could be used as rockfill material. The relationships between the mechanical characteristics and mudstone content are statistically analyzed according to the testing results.

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MODE ANALYSIS OF SLIDING PLANE FOR FOUNDATION PIT ANCHOR

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2003, 22 (02): -337 doi:
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The sliding plane mode of soil anchor is briefly analyzed. On the basis of bearing capacity characteristics of the soil anchor and equilibrium of sliding and antisliding forces，the inclination of sliding plane is derived precisely for the stability analysis of foundation pit anchor. Finally，comparison is made of the proposed method and tranditional method used to determine the sliding plane of soil anchor.

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SYSTEMATICAL RESEARCH ON THE STABILITY OF HIGH ROCK ENGINEERING SLOPE AND ITS CONTROL

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2003, 22 (02): -341 doi:
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STUDY ON THE DAMAGE CONSTITUTIVE MODEL FOR ROCK AND THE EFFECTS OF UNDERGROUND EXPLOSION

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2003, 22 (02): -342 doi:
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[PDF 96 KB] (836)

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