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2003, 22 (07): -0 doi:
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ANALYSIS ON STABILITY OF SURROUNDING ROCKS OF SHUIBUYA UNDERGROUND PLANT BY THREE-DIMENSIONAL FAST
LAGRANGIAN METHOD

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2003, 22 (07): -1047 doi:
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[PDF 1201 KB] (1183)

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The construction and excavation process of underground plant of the Shuibuya Project are simulated by three-dimensional fast Lagrangian method(FLAC-3D). The pattern of deformation caused by excavation and stress state in surrounding rocks of the chamber group under complex geological conditions are researched. The distribution of plastic areas and the stability of surrounding rocks are analyzed. And the bolting is performed to support the vault of tail-race tubes.

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ENERGY ANALYSIS OF SURROUNDING ROCKS IN UNDERGROUND ENGINEERING

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2003, 22 (07): -1054 doi:
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[PDF 208 KB] (1234)

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Rock burst is a kind of catastrophe during the excavation in underground projects. It is a process of energy release and rock block casting. So the energy change in the surrounding rocks of underground projects must be analyzed. The elastic strain energy of rocks before excavation，energy release and gathering in surrounding rocks，the condition of energy transfer，and the energy variation of rocks in front of cutting face are studied. When the strain energy reaches its limit energy storage in one point，the surplus energy will be released and produce plastic deformation，or rock fracture，and the remaining energy will shift into the deeper part of the rock. If the energy is especially large and can not shift into the depths，the rock burst will take place. This theory has been successfully used to prevent rock burst.

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COUPLING ANALYSIS ON HYDRAULIC FRACTURING PROCESS OF ROCK

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2003, 22 (07): -1060 doi:
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[PDF 388 KB] (1147)

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Hydraulic fracturing is a typical illustration of coupling between seepage and stress in rock failure process. Based on Biot seepage mechanics equations and elastic damage theory，the coupling model between seepage and stress in rock failure process is proposed. By using Coupling System of Flow and Solid in Rock Failure Process Analysis，F-RFPA2D，the initialization and propagation of crack in hydraulic fracturing process is simulated to analyze the law of permeability evolvement，seepage-stress coupling mechanism and unstable behavior of rock.

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STUDY ON ROCKBURST CONTROL IN DEEP-SEATED
HARD ORE DEPOSIT

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2003, 22 (07): -1067 doi:
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[PDF 269 KB] (1283)

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Dongguashan Copper Mine is the first rockburst-prone deep-seated metal ore deposit in China where rockburst control study has been performed. The rockburst proneness of typical rocks of the deposit and the properties of rockbursts of the workings at the mine are analyzed with the results of laboratory tests，namely，tension tests，complete stress-strain tests and tests of stress relaxation under the deformation at peak load，and in-situ rockburst information recorded during the drifting of the development workings. The stope structure parameters and mining steps of the deposit are optimized with numerical simulation method based on energy release rates in order to control rockbursts of stope. On the basis of this study，the principles and measures of rockburst control in the course of the mining in the mine，that is，control of energy release，reduction of energy storage，rational support and rockburst monitoring，are provided and discussed.

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ON THE RELATION BETWEEN INTERLAYER GLIDE CAUSED BY COAL EXTRACTION AND THE SHAFT RUPTURE OCCURRING IN COAL
MINES IN HUANGHUAI AREA

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2003, 22 (07): -1072 doi:
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[PDF 278 KB] (971)

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Based on the investigation of a large number of coal mine shafts in Huanghuai area，a comprehensive analysis is made on the characteristics of those ruptured shafts in this area. A review is presented on several different opinions about the mechanism of shaft rupture. The relation between interlayer glide caused by coal extraction and the shaft rupture is studied. The method for reinforcement of ruptured shafts is put forward and some measures to prevent rupture of the shaft wall are proposed.

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INFLUENCE OF MINING ON FLOOR INFILTRATION COEFFICIENTS

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2003, 22 (07): -1078 doi:
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[PDF 232 KB] (852)

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The key of mining the coal seam threatened by confined water in Ordovician limestone is the understanding of the failure mechanism of floor rockmass and determination of affecting depth by mining. The affecting depth is usually acquired according to the change of permeability in floor rockmass. The permeability of the floor rockmass is closely related to the stress field of floor rockmass. Based on in-situ measured data，mechanical parameters of rock and method of displacement back analysis，the floor stress field of coal face No. 1237 in Zhaogezhuang Mine is firstly given，then the permeability coefficients of floor rockmass is computed，and lastly the relationship between stress field and permeability coefficients is determined.

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CALCULATION FOR MAXIMUM SUBSIDENCE INDUCED BY COAL SEAM MINING WITH DIFFERENT DIP ANGLES

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2003, 22 (07): -1083 doi:
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[PDF 544 KB] (1067)

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The maximum subsidence induced by mining bedding ore(such as coal seam) is an important parameter for estimating the degree of surface movement and deformation. The relations are dealt with between ground maximum subsidence and geometric factors of extraction. A seam-dip-angle-based model of maximum subsidence is established to reflect the comprehensive influence of geometric and mining factors，as well as the effects of bedding structure and extraction size. The research results have laid a foundation for the construction of unified subsidence model suited for the whole range of seam dip angle.

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IMPROVED METHOD OF DYNAMIC TIME-HISTORY
ANALYSIS OF TUNNEL

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2003, 22 (07): -1088 doi:
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[PDF 224 KB] (912)

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Based on Newmark step-by-step implicit integration method，an improved method is put forward to improve calculation efficiency，and some questions are pointed out to which attention should be paid when initial static stress field is dealt with in dynamic nonlinear analysis. The implicit integration and explicit integration methods are applied，respectively，to calculate the dynamic response of a tunnel due to train vibration. It is shown that the improved method raise remarkably the calculation efficiency of implicit integration method and the required time of using implicit integration method is much less than that of using explicit method. It is suitable to select step-by-step implicit integration method to solve the questions of dynamic response for tunnel and some underground structures.

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CHARACTERISTICS OF ROCK STRENGTH AND FAILURE UNDER TRIAXIAL COMPRESSION ANALYZED BY TWIN SHEAR THEORY

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2003, 22 (07): -1093 doi:
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[PDF 311 KB] (1111)

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The characteristics of the rock strength and failure under triaxial compressions are theoretically analyzed in detail with the twin shear theory and the results are compared with experimental data. The research work shows that on the aspect of rock strength，the analytical results match the experimental data very well，but on the aspect of fracture orientations，there are some differences between analytical results and experimental data. The main reason may be that the fracture orientations are more sensitive to the inner micro-structures of rock and the condition of testing surface than the strength. However，as one kind of macro-strength theories，the twin shear theory is still an effective tool in analyzing the rock failure and strength under multi-axial stress condition，and it also has many other profits such as simplicity in formulae and convenience for use in practice.

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ROCK MECHANICS PROPERTIES UNDER THE STRESS FIELD OF
TRUE UNIAXIAL COMPRESSION

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2003, 22 (07): -1099 doi:
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[PDF 256 KB] (884)

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There is an important difference between the properties of material mechanics and those of structural mechanics. The physical meaning of complete stress-strain curve of rock at each stage is discussed under true uniaxial compression. It is concluded that the curve before the peak basically expresses properties of material mechanics of rock and the curve after the peak expresses in fact reflects the viewpoint of structural mechanics. A new method is presented for determining the stress-strain curve for a rock cylinder with a medium thickness under uniformly distributed compression and has a good result.

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LARGE-SCALE TRIAXIAL TEST STUDY ON DEFORMATION AND STRENGTH CHARACTERISTICS OF ROCKFILL MATERIALS

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2003, 22 (07): -1104 doi:
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[PDF 366 KB] (1261)

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The test results of two rockfill samples are obtained with large-scale testing equipment. Based on these results，some useful conclusions are drawn from the analysis of deformation in each direction and shear strength properties of the rockfills. Thus，the exponent formulations of the relationship between deviator stress and axial strain or lateral strain and axial strain are proposed，respectively. Besides，the failure envelopes of rockfills in the coordinate plane of octahedral shear stress and octahedral normal stress also can be described by the exponent formulation. At the same time，the inherent mechanism of experimental phenomena is discussed. The relations among dilation，particle breakage and rearrangement are analysed，and the concept of reciprocal transformation of elastic dilatancy and plastic dilatancy is put forward.

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ANALYSIS ON THE STABILITY OF ROCK SLOPE WITH
SURFACE INFILTRATION

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2003, 22 (07): -1112 doi:
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[PDF 214 KB] (995)

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An extended Mohr-Coulomb failure criterion is used to allow for shear strength variations as a result of changes of matrix suction. The landslide mechanism of rock slope under the influence of surface infiltration is discussed. By means of the limit equilibrium theory of rigid body，an analysis method on rock slope stability considering surface infiltration，which is called improved non-equilibrium push transmission method，is proposed and a program for checking the stability of rock slope with the function of matrix suction and temporary additional water load considered，is worked out. This program is applied to the analysis on rock slope stability with the presence of surface infiltration. The results show that the analysis method and program in this paper are reasonable and reliable and surface infiltration will bring harmful influence on the stability of rock slope.

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_{FUZZY HIERARCHY ANALYSIS ON DECISION MAKING OF ROCKMASS SLOPE TREATMENT BASED ON
ENTROPY WEIGHT}

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2003, 22 (07): -1117 doi:
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[PDF 162 KB] (1091)

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In light of the fact that the decision making of treatment schemes of slopes is a comprehensive multi-objective and multi-hierarchical judgment problem，and a fuzzy property of its evaluation indexes is involved，a fuzzy hierarchy analysis on decision making of rockmass slope treatment based on entropy weight is presented in this paper. According to the two-two index comparison，the triangle fuzzy numbers are adopted to establish judgment matrix. Thus the unbalance of judgment matrix caused by traditional hierarchy analysis is improved. The entropy weight is given through fuzzy interval arithmetic based on level sets and optimistic index. Then the treatment schemes of rockmass slope are evaluated on the basis of entropy weight. The assessment of treatment schemes of critical rockmass on the Slate Mountain is taken as an example，and the application of the method is discussed in detail. The result shows that fuzzy analysis hierarchy process of decision making for rockmass slope treatment based on entropy weight is scientific and reasonable，and has important value for engineering application.

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SLOPE3D —— A THREE-DIMENSIONAL LIMIT EQUILIBRIUM ANALYSIS SOFTWARE FOR SLOPE STABILITY AND ITS APPLICATION

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2003, 22 (07): -1121 doi:
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[PDF 345 KB] (1495)

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In order to pursue three-dimensional limit equilibrium analysis methods to widely practical applications，an interactive visualization system software SLOPE3D for slope stability analysis has been developed. It contains the pre-processor，the limit equilibrium analysis solver and the post-processor. In the pre-processor，the construction of three-dimensional geological model of the slope structure provides geoinformation presentation for the limit equilibrium solver. In the post-processor，the effective three-dimensional visualization of data sets can assist the user with interpretation and analysis of the calculation results. The SLOPE3D system combines 3D visualization of geoinformation in slope engineering with limit equilibrium analysis for slope stability. Because of its user-friendly interface and 3D graphics capabilities with high quality，the geotechnical engineers can easily apply SLOPE3D to practical engineering problems.

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AUTOMATIC SEARCH FOR COMPLEX UNSTABLE ROCK BLOCKS AND THE JUDGMENT OF UNSTABILITY MODE
——BASED ON 3D NETWORK SIMULATION OF RANDOM FRACTURES

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2003, 22 (07): -1126 doi:
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[PDF 255 KB] (1147)

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According to the 3D network computer simulation，the numerical model of probability statistics for distribution of discontinuities of rockmasses is established. A computational program for the method has been accomplished. With the program all the potential movable rock blocks can be found out of all the finite rock blocks which has free face exposed，and the geometry parameters and geometrical forms of the blocks determined. Then the stability analysis will be performed with mechanical parameters of the discontinuities.

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ANALYSIS ON STRUCTURAL HOMOGENEITY OF ROCK MASS BASED ON DISCONTINUITY DENSITY

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2003, 22 (07): -1132 doi:
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[PDF 306 KB] (1241)

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It is a kind of conventional method to analyse the structural homogeneity of rock mass according to statistical data of discontinuity orientation. However，if the discontinuity orientation is similar in an area，this method should not be used to evaluate homogeneity of structural populations. So a new method is put forward to analyse the structural homogeneity of rock mass based on discontinuity density，and it is successfully applied to analysis on the structural homogeneity of discontinuities for sideslip surface in a large hydropower project in Southwest China.

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NEW ELEMENT FORM IN THE NUMERICAL SIMULATION OF BOLT-REINFORCED STRUCTURE

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2003, 22 (07): -1137 doi:
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[PDF 264 KB] (994)

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A new element form，which is based on the displacement interpolation function of triangular or quadrangular solid element and the stiffness matrix of one-dimensional truss element，is introduced into the analysis on bolt-reinforced underground structure. By using the new developed method，the bolt can be freely added or removed at the arbitrary excavation step in the finite element analysis of underground structure，and the bolt nodes need not be previously considered or arranged in the mesh generation procedure，so that the work of pre-process or mesh division procedure in finite element method can also be much reduced.

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CALCULATION METHOD OF SUPPORT LENGTH FOR STRETCHED BOLTS

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2003, 22 (07): -1141 doi:
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[PDF 246 KB] (1295)

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Based on Mindlin¢s solution of displacement，an elastic solution of stretched bolts is derived. The mechanical characteristics of the stretched bolts are analyzed and a method for calculating support length of stretched bolts is obtained. The effective length of bolt support is calculated for different rocks. Some factors affecting effective length of bolt support are analyzed. A reference principle for design of bolts is provided for projects.

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ULTRASONIC TESTING ON THE LOAD MONITORING OF PRE-STRESSED CABLE AND ITS APPLICATION

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2003, 22 (07): -1146 doi:
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[PDF 263 KB] (940)

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In view of the insignificant change of ultrasonic velocity and amplitude of the concrete under low load，the ultrasonic weighted spectrum parameter obtained from wavelet treatment is taken as the intermediate index during load monitoring of pre-stressed cable. The rating curve of the weighted wave spectrum parameter and load on the concrete anchored pier during pretension of pre-stressed cable is standardized. Based on those standardized curves，the pre-stress of cable is calculated by the ultrasonic monitoring data of concrete anchored pier. The application result of this technology to a slope project shows that when load change exceeds 50 kN，the change of weighted wave spectrum parameter is obvious and this can reflect the change course of the loss of pre-stress. The ultrasonic testing results have a good agreement with load sensor results.

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RESEARCH ON THE EXPANSIVE SOFTROCK IN YANJI REGION

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2003, 22 (07): -1151 doi:
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[PDF 358 KB] (931)

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The expansive softrock in Yanji region has not been recorded in the published papers. Recently，several landslides occurred there during building of high grade road. The unexpected failure of slopes aroused close attention in the local geoengineering field. A series of tests，including creep test，direct shear test，triaxial compression test，expansion test，disintegration test and XRD technique，show that expansive softrocks exist in Yanji region and belong to high expansive softrocks by the national standard. The clay there is composed mainly by montmorillonite and mixed-layer mineral I/S with middle mixed-layer ratio. Based on research on mechanisms of failure of the slopes，the improving methods are put forward. The research on the expansive softrocks is of great significance for the treatment of slope of expansive softrocks in Yanji region.

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STUDY OF DYNAMIC PERFORMANCE OF CEMENT-IMPROVED SOIL

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2003, 22 (07): -1156 doi:
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[PDF 197 KB] (981)

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In order to enlarge the usage extent of base materials of rapid transit railway foundation，the dynamic triaxial test is made on cement-improved soil. The dynamic performance of cement- improved soil under repeated load of train is analyzed. The variation and influence factors of critical dynamic stress，accumulated plastic deformation，elastic deformation and resilient module of cement-improved soil are studied. It can be concluded that the dynamic performance of cement-improved soil meets the design demand of rapid transit railway subgrade.

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UPLIFT TEST STUDY ON REINFORCED AEOLIAN SAND (I)
——PROPERTIES AND UPLIFT MODEL TESTS ON
SPREAD FOUNDATION

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2003, 22 (07): -1161 doi:
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[PDF 345 KB] (960)

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In Hobq sand land and Muus sand land of Ordos plateau and Tengger sand land and Ulanbuh sand land of Alxa plateau，the information of the aeolian sand is investigated in field. The physical and mechanical properties of specimens are tested and studied of undisturbed soil and disturbed soil. The mineral chemical composition is analyzed. According to the property of geosynthetics，the friction properties of aeolian sand and geogrid are studied，and the method for enhancing the mechanical properties of aeolian sand is put forward. Uplift properties of spread foundation of reinforced aeolian sand is studied including stress，displacement，deformation，failure mechanism and bearing capability.

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ANCHORAGE BEHAVIOR OF POST-EMBEDDED BARS IN CONCRETE SUBJECTED TO TENSION

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2003, 22 (07): -1169 doi:
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[PDF 233 KB] (1198)

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In this paper，the failure mechanism and mode of post-embedded bars in concrete subjected to tension is investigated. The ultimate anchorage strength of the bars under mixed bond-cone failure mode is analyzed. Comparison with test results is made. The influence of parameters such as bond thickness，behavior of bonded materials，strength of concrete，anchorage depth，group bar effect，on the anchorage behavior is discussed also.

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EFFECT OF SHIELD TUNNELING ON MECHANICAL
PROPERTIES OF SOILS

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2003, 22 (07): -1174 doi:
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[PDF 272 KB] (1101)

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The influence of shield tunneling on surround soils is studied through the monitoring in situ. The soil disturbance is analysed by variation of the stress state due to shield tunneling，and the definition of the stress disturbance degree is presented. The mechanism of the ground surface settlement is also studied. The statistical relationship is proposed between mechanical properties of soils and the stress disturbance degree.

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FEM ANALYSIS ON WAVE PROPAGATION IN SOILS INDUCED
BY HIGH SPEED TRAIN LOADS

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2003, 22 (07): -1180 doi:
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[PDF 625 KB] (945)

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Analysis is made on wave propagation in soils under high speed train loads by two-dimensional finite element method. The train loads are simplified and the influences of different characteristic of soils are considered. Different material parameters for various area are adopted. Then the displacement and acceleration of the ground can be obtained. The presented method applies the same velocity of loads and no change of ground in the moving load direction.

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APPLICATION OF SEEPAGE CALCULATION FOR MULTI-LAYERED STRONG PERMEABLE SOIL

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2003, 22 (07): -1185 doi:
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[PDF 448 KB] (1006)

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Aiming at the large area，the multi-layer level distributing，and the complicated terrain of the permeable foundation of levee，the finite element program is developed for two-dimensional seepage in horizontal plane with multi-layer medium. In the program，the relationships between each permeable layers and the surface are established through leakage through weak permeable layer，the bleeder well calculation formula of permeable double-layer and the modified method on well point. This is a predigested method using two-dimensional method to simulate three-dimensional problems. In the method，the vertical seepage of the strong permeable layer and horizontal seepage of the weak permeable layer are ignored，and the flow in the strong permeable layer and the leakage through weak permeable layer between two layers are emphasized. The proposed method is applied to several engineering practices of North River Levee，and some difficult engineering problems are solved.

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EVALUATION METHODS TO REGRESSION RESULT OF
EXPERIMENTAL DATA

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2003, 22 (07): -1191 doi:
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[PDF 195 KB] (1040)

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Regression is usually used to determine the relation among some testing parameters. Experimental data of rock mechanics are often dispersive，and the reliability of the regression result must be evaluated. In this paper，two methods to review the error of regression are given on the Coulomb criterion. One is to regress again after decreasing or repeatedly using some data. The other is to do‘hypothetical experiments’after arranging the specimens in various confining pressures. A certain range of the rock parameter like internal friction angle with certain reliability can be given. The effect of confining pressure range on the regression results of strength criterion is also discussed.

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SUBGRADE REACTION COEFFICIENT METHOD OF NEW-STYLE PRESTRESSED ANCHOR SHEET-PILE RETAINING WALL WITH ELASTIC RESTRAINT

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2003, 22 (07): -1196 doi:
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[PDF 326 KB] (1096)

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Based on sheet-pile retaining wall and anchored anti-slide pile，the prestressed anchor sheet-pile is developed as a new type of retaining structures. On the basis of structure matrix method，combined with engineering characteristics，and with consideration of elastic restraint of anchorage cables，the relationships of earth pressure along with displacement，continuous conditions of displacement and internal force at preliminary shaft，and effect of anchorage part deformation on displacement of piles，stiffness matrixes of anchorage part and bearing part are established，respectively. Displacements and moments of metope pile，stresses and strains of anchorage part，and tension forces of anchor cables are all calculated by using a corresponding program. The calculated results have preferable regularity and agree with those of other methods，and this may be referenced in other related engineering projects.

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DETERMINATION OF DEEP FOUNDATION PIT SUPPORTING SCHEME BY USING THE GRAY SYSTEM THEORY AND METHOD

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2003, 22 (07): -1203 doi:
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[PDF 186 KB] (1161)

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According to the principle of gray correlation analysis，a comparison data series are composed by collecting the ideal index values of multiple factors of deep pit foundation supporting scheme to affect decision making，meanwhile the reference data series are also organized by collecting the actual indexes with the same effect to the decision making of foundation pit. The optimizing method on the supporting scheme is presented based on the model of gray optimal theory and combining with the practical example. The proposed method is simple with clear concept，and can be easily applied to the practical projects.

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STUDY AND APPLICATION OF GROUTING TECHNIQUE WITH BEARING PLATE

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2003, 22 (07): -1207 doi:
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[PDF 197 KB] (945)

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The development history and present state of grouting technique are summarized. The existing problems and the development trend are also illustrated at the same time. The construction measures of adding bearing plate on the ground are taken so as to enhance the effect and the reliability of improvement. The work mechanism and improvement effect are systematically analyzed. The corresponding design principles and the structural measures are given. The method has been applied to the engineering practice successfully.

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DESIGN OF RETAINING WALLS WITH ANTI-SLIDE TIE

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2003, 22 (07): -1211 doi:
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[PDF 242 KB] (1357)

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The design theory of retaining walls with anti-slide tie is studied systematically，and a new method on the design of retaining wall is presented. A nonlinear earth pressure coefficient formula of the earth pressure changing with retaining wall displacement is proposed，and load-deformation relationships of anti-slide tie under horizontal loading are discussed. The proposed method is applied to design of retaining wall with anti-slide tie. Through a case study，the results confirm that the proposed method is reasonable.

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RESEARCH ON THE REINFORCEMENT TIME FOR HAZARDOUS BUILDINGS IN UNSTABLE NEARBY CONDITIONS

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2003, 22 (07): -1216 doi:
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[PDF 223 KB] (880)

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Based on the engineering practice and analysis，the possibility is shown for endangered buildings to be underpinned under the condition that nearby basement work has not completed yet. Good results will result from scientific underpinning time and reasonable parameters. A sample is taken to show how to treat the endangered buildings with nearby basement work.

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SOME PROBLEMS IN DESIGN OF ROCK SOCKETED PILE

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2003, 22 (07): -1222 doi:
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On basis of the design of rock socketed pile，some problems are discussed，concerning the design method，design standard，design parameter and the standard on loading test of pile. The study results show that the design method should be based on the bearing behaviors of pile，the design standard should be controlled by the strength and the deformation of pile foundation，and the parameter used in design should accord with the load transfer law of pile.