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2005, 24 (07): -0 doi:
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2005-07期目录

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A NOVEL NUMERICAL ANALYSIS METHOD FOR ROCK MASSES —SUPERPOSED ELEMENT METHOD

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2005, 24 (07): -1093 doi:
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Superposed element method (SEM)，a novel numerical analysis method for rock masses，is proposed in this paper. At first，for the complicated rock masses containing many discontinuities，the mesh of the whole domain without any discontinuity and the mesh for each discontinuity，together with its adjacent zone，are generated separately. The displacement field is interpolated in each mesh and superposed together. Then，the generalized stiffness matrix and load vector in the equilibrium equations are formulated by using the virtual work principle，and the numerical integration method is discussed. Finally，two numerical examples of plane stress problem are studied by the new method，and the results are very close to those calculated by using FEM. The most distinguished characteristic of SEM is that its mesh generation is simplified greatly by partitioning the mesh of complicated rock mass into several separated simple meshes. The new method can be expanded to solve three-dimensional and non-linear problems directly，and is expected to be widely used in the deformation and stability analysis of complicated rock masses.

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PROPERTIES OF ELASTO-PLASTIC MATRIX Dep AND A CRITERION ON LIMITING STATE OF SLOPE STABILITY BY FEM

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2005, 24 (07): -1099 doi:
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It is proven that under assumption of the associated flow rule，the elasto-plastic matrix Dep is positive definite for hardening materials，positive semi-definite (the rank deficiency being one) for perfectly plastic materials and indefinite for softening materials，respectively. Based on the fact that Dep is singular for perfectly plastic materials，it is stated that if a slope arrives at the state of limit equilibrium，a layer of elements must go through the slope from the bottom of the slope to the top，each element in the layer being in plastic state. Hence，it is rational that the contour plots of the equivalent plastic strain or the plastic work are used to judge if slopes reach the limit equilibrium state. The paper makes a qualitative analysis for the abnormal phenomenon in which the plastic zones are usually overestimated in analyzing slope problems by FEM. The skill for overcoming such an abnormal phenomenon is proposed as well.

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A TRI-PARAMETER STRENGTH THEORY (TWIN t 2) AND ITS APPLICATION FOR ROCK MATERIALS

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2005, 24 (07): -1106 doi:
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Strength theory of rock is important in safety evaluation and designs of the civil，mining and hydraulic rock engineering，and has important significance in the study of rock mechanics. In this paper，the tri-parameter strength theory under complex stress states, called twin ，is derived. At first，the relations among the compressive strength，tensile strength and shear strength are proposed. Secondly，the brittle failure of rock is analyzed by using the developed twin strength theory and compared with the available experimental data for some rock materials. The results are shown to be satisfactory.

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LONGITUDINAL SHEAR TRANSFER OF TUNNEL AND ITS 1D ANALYTICAL SOLUTION

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2005, 24 (07): -1110 doi:
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By analysis of the internal force components in longitudinal and cross sections of a circular tunnel and their correlations under uneven subsidence，based on the elastic foundation beam(EFB) theory and potential theory，the concept of longitudinal shear transfer and its solution are proposed. In addition，additional internal forces produced by longitudinal shear transfer under 4 typical forms of subsidence are analyzed and it¢s concluded that the additional internal forces vary significantly with the subsidence forms and the critical values turn out not to be at the places of maximum subsidence. It¢s suggested that the effect of longitudinal shear transfer should be taken into consideration for improved tunnel design.

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ANALYSIS OF ENERGY DISTRIBUTIONS OF MILLISECOND BLAST VIBRATION SIGNALS USING THE WAVELET PACKET METHOD

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2005, 24 (07): -1115 doi:
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Blast vibration analysis is the foundation for studying the control of blasting vibration damage. Based on the characteristics of short-time non-stationary random signals，this paper investigates the energy distributions of blasting vibration signals by means of the wavelet packet analysis technique. In this paper，the characteristics of wavelet transform and wavelet packet analysis are briefly introduced. Then，6 sets of blasting vibration signals of multi-interval-time in millisecond blasts are analyzed by using the wavelet packet analysis technique with MATLAB. Energy distributions for different frequency bands are obtained. The results show that the wavelet packet analysis method is an effective means for studying seismic effect induced by blasting，and is especially useful for establishing the velocity-frequency criteria.

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STUDIES ON MICROCOSMIC CRACK DAMAGE PROPERTIES OF A RED SANDSTONE WITH DIGITAL IMAGE TECHNIQUE

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2005, 24 (07): -1123 doi:
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This study aims to investigate experimentally the relation between dynamic damage state and mechanics responses of a red sandstone. Cracks and holes on the surface of specimen are observed and recorded synchronously with deformation responses. The images of cracking of specimen in different water content states are analyzed by a digital image technique，and quantitative results for surface cracking process are obtained. In order to obtain the quantitative description of microcosmically prefabricated cracks development，two physical quantities，of damage tensor and crack degree，are proposed for quantitatively estimating dynamic and gradual damage development of the red sandstone using microcosmic cracking in water content state. Further understanding about the damage evolution law of red sandstone under single axis compression though applying microstructure method is also obtained.

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A NEW METHOD CONSIDERING INTER-LAYER INTERACTIONS FOR ANALYSIS OF MULTI-LAYERS LANDSLIDES

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2005, 24 (07): -1129 doi:
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here are complex landslides with several layers of slipping plane in the geotechnical engineering. In this paper，a new method to analysis the multi-layers landslide is presented. Every layer of sliding masses when calculating the slope stability and landslide-thrust distribution is analyzed. The upper layer of the sliding mass is analysed by using the common transfer coefficient method. When the lower layers of the sliding masses are analysed，the weight of the upper layer but the effects of the upper mass on the layer below can be ignored. The method was applied to a practical project，and the results show：(1) the safety factor of the slope calculated by the new method is with the same as the general method；(2) because the anti-sliding pile intercepts the sliding mass，the landslide thrusts of different layers of sliding mass act on the pile separately. Therefore，the total landslide thrust is varied with different methods；(3) when the upper sliding mass has different design safety factors，the landslide-thrust of the upper mass and the total landslide-thrust are different. The calculated results by the new method make the design of anti-sliding structures more reasonable.

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ANALYTICAL CALCULATIONS OF CRITICAL ANCHORAGE LENGTH OF BOLTS

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2005, 24 (07): -1134 doi:
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Up to now，the analytical estimation of critical anchorage length，which is a very important parameter in bolts design，is not available. A perfectl elasto-plastic load-transfer model is used to derive an analytical solution for this problem. Based on the developed analytical solution，an analytical critical anchorage length (ACAL) formulation，which relates the anchorage diameter，anchorage deformation modulus，and anchorage layer characteristic coefficient with the critical anchorage length，is obtained. The analytical solution also shows a trend of more uniform distribution of the frictional resistance when the anchorage length is less than ACAL. The frictional resistance distribution becomes very uneven when the anchorage length is larger than half of the ACAL. Further study shows that the ultimate bearing capacity of the bolt increases significantly as the anchorage length increases within half of the ACAL，while the anchorage length is larger than half ACAL the effect of anchorage length on bearing capacity is limited. Based on the above findings，it can be seen that half ACAL is a very important parameter indicating the efficiency of the bolts. Thus，it is defined as“engineering critical anchorage length”and it is suggested that the designed anchorage lengths of bolts should be below their engineering critical anchorage lengths. Two convenient methods for practical use of estimation of the engineering anchorage length are presented with examples.

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AN EXPERIMENTAL STUDY ON THE COMPACTION OF WATER-SATURATED OVER-BROKEN ROCK

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2005, 24 (07): -1139 doi:
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The deformation characters of the broken rocks are the important factors that affect the roof caving and surface subsidence above goaf in coal mining. With a compaction device，especially designed for broken rocks，the deformation character tests of water-saturated three broken rock samples (coal，shale and sandstone) were tested in a MTS815.02 test system. It was found that stress-strain properties of the samples of broken rocks depend on grain size and rock strength. The results show that the stress-strain relation can be approximated as a power function. In addition, the strains of specimens decrease with the increase of strength under the same stress conditions，the strain increase of course grained specimens is smaller than that of fine grained specimens in the first period of loading process，and the water-sutured broken rock specimens undertake larger stains than the rock specimen of natural water content under the same level of stress. These test data are useful for further study.

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EFFECT OF SAMPLING STRATEGIES ON BACK ANALYSIS FOR PERMEABILITY COEFFICIENTS OF FRACTURED ROCKS

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2005, 24 (07): -1145 doi:
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Using observation data of underground water level proves to be a comparatively reliable method for inversion analysis of seepage parameters for fractured rocks. Generally，observation data are gained randomly without considering the spatial continuity of underground water level. In this paper, the spatial correlation structure of underground water level is analyzed by using geostatistics. The total estimate errors is used for investigating the result of back analysis for seepage parameters of fractured rock mass under three different sampling scheme .The result shows that optimized sampling scheme can decrease the sampling expenses while insuring the accuracy. The error produced in random samping is bigger than that of optimized sampling scheme when the number of observation data is the same. It is not obvious that increasing the number of random observation data can improve the result of back analysis.

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QUESTIONING THE VALIDITY OF THE BRAZILIAN TEST FOR DETERMINING TENSILE STRENGTH OF ROCKS

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2005, 24 (07): -1150 doi:
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The extensively used formula for estimating the tensile strength of rocks under the Brazilian test is based on the 2D elastic theory and only suitable for very long or very short cylinders. However，the size of specimen in practice does not meet these preconditions. Under 3D conditions，it is found out that height- to-diameter ratio and Poisson¢s ratio are two factors influencing the stress distributions in rock cylinders. Through 40 3D FEM simulations，the influences of the height-to-diameter ratio and Poisson¢s ratio upon the stress distribution within the specimen were studied. It is found that the largest tensile stress within the specimen is always at the center of end surface. A fitting formula of largest tensile stress is presented. Lastly，the largest equivalent stresses bases on Griffith strength theory and Mohr strength theory were calculated. And it is found the largest equivalent stress is not at the center of the end surface of cylinder but always at the loading point of the end surface. Therefore，the Brazilian test is not suitable to measure the tensile strength of rock-like materials.

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STUDY OF CONSTITUTIVE MODEL FOR ROCK INTERFACES AND JOINTS UNDER NORMAL CYCLIC LOADING

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2005, 24 (07): -1158 doi:
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The constitutive models for rock interfaces and joints under cyclic normal loading are reviewed. From many tests it is concluded that the joint loading，unloading and reloading follow hyperbolic responses，and result in irrecoverable closure deformation with hardening of the joints. Based on the hyperbolic constitutive models，it is supposed that the unloading and reloading curves have the same asymptote which represents the maximal closure of the joint. For every loading step curve，the initial normal stiffness，which is defined as the normal stiffness at the zero normal stress point on the curve，is calculated from the initial normal stiffness of the previous loading and unloading curves. New parameters are introduced to represent the convergence velocity of constitutive curves and the irrecoverable closures，with their values depending on the rock types，the geometric characters and on the infill mineralogy of the rock interfaces and joints. With different values of the parameters，this model can be made equivalent to other models reviewed. Comparison with normal cyclic loading tests on natural clean joints and filled joints shows that this model could describe the constitutive relations of rock interfaces and joints with higher accuracy.

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MATHEMATICAL MODEL AND ANALYSIS ON THE RELATION BETWEEN PRESSURE AND SPEED OF COLLAPSE DURING COLLAPSE OF LOESS

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2005, 24 (07): -1164 doi:
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On the basis of energy conservation during the collapsible process of loess，a relation between pressure and collapse speed during collapse of loess was built. The model parameters and the curves of the relation were obtained by experiment. Based on the model and the curve，the obtained conclusions are：the higher pressure is，the higher collapsible speed is；the larger quantity of collapse is，the larger collapse pressure of origination is，and the collapsible speed has the character of salutation.

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THE CHARACTERISTICS OF THE BEARING CAPACITY OF BUCKET FOUNDATION

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2005, 24 (07): -1169 doi:
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The finite element software(ABAQUS) was used to simulate the bearing capacity of the bucket foundations with different height-to-diameter ratios. The characteristics of the bearing capacity of the foundations under the vertical loading，the horizontal loading and the coupling loadings were analyzed. The numerical results were compared with that of experiments. It is shown that under a critical vertical loading，the horizontal bearing capacity increases with the increase of the vertical loading，but decreases with the increase of the vertical loading when the latter is larger than the critical loading. The bearing capacity，especially the horizontal bearing capacity，increase obviously with the increase of the height-to-diameter.

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MITIGATON OF DIFFERENTIAL SETTLEMENT BETWEEN EARTH STRUCTURE AND ROAD ON SOFT CLAYS

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2005, 24 (07): -1173 doi:
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For low embankment road on soft subsoils，since the traffic loading is cyclically exerted on the soft subsoils，there always exists excess pore pressure at a certain depth in the soft subsoils. Therefore，settlement under the traffic load is continuously developed in the long term. However，the crossing structures such as bridge abutment and box culvert are generally supported by piles and small settlement will happen. Thus，large differential settlement between road and crossing earth structures may occur. The differential settlement will affect or even obstruct vehicle transportations. In order to reduce this differential settlement，many methods have been proposed to provide the transition zone between pile-supported structure and road. In Japan，conventionally，three repairing approaches have been used：(1) to overlay a new pavement on the existing pavement for some periods (overlay repairing)；(2) to set a concrete cushion slab under pavement of transition zone；and (3) to cut the pile top and reconstruct the structure. These conventional methods are either not effective or not economic. The effective transition zone treatment is to use piled embankments，which may use different pile types，namely，timber piles，stone columns，sand compaction piles，lime columns，soil-cement columns，and driven or cased in-situ concrete piles. This paper introduces a repairing project of transition zone of a low embankment road on soft Ariake clay，Saga，Japan. In this project the soil-cement columns were used to improve the soft subsoil under the transition zone called column approach (CA) method. The design procedure and parameters are introduced briefly at first. Then，the field case is introduced in detail. The results from field monitoring show that when the differential settlement is over some value，overlay repairing is not economic and the approach cushion does not work well while CA method mitigates the differential settlement more effectively.

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ANALYSIS OF STRESSES IN TRAIN-INDUCED GROUND

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2005, 24 (07): -1178 doi:
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Based on the theory of Timoshenko beam on elastic foundation and its dynamic solution under moving loads，the train-induced reaction forces between ground surface and embankment are calculated. Exerting the reaction forces on the ground surface，the corresponding steady-state stresses in ground are obtained by integrating the basic solution of a moving point load on the surface of an elastic half-space. The results are valid only for train speed lower than Rayleigh wave velocity in ground. Compared with the in-situ testing results of train vibration，including embankment displacement and velocity，it is shown that the presented model is reasonable. The variation of stresses with spatial co-ordinates and time is presented. Characters and distribution patterns of stresses are studied. The dynamic stresses seem to be a kind of particular cyclic loads，which are mainly compression stresses. The distribution of dynamic stresses is similar to that of stresses induced by static load (such as strip load) on the ground surface，but changes with train motion. The influence of ground properties and train speed on stresses is also presented. It is found that the influence of shear modulus on stresses is dependant on train speed，and the influence of Poisson¢s ratio on horizontal stresses is significant. The train speed also affects the stress distribution greatly，especially when speed ratio is over 0.6.

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A MESHLESS MANIFOLD METHOD FOR CRACK PROPAGATION ANALYSIS

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2005, 24 (07): -1187 doi:
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A meshless manifold method (MMM) is presented to analyze the problems of crack propagation， especially the advantages of MMM for irregular cracks. The shape functions in this method are formed by the partition of unity and the finite cover technology，so the shape functions are not affected by discontinuous domains and crack problems can be more properly treated. For strain localization problems，the shape functions can be more effectively established，compared with other methods in which the tips of the discontinuous cracks are not considered. Compared with the conventional numerical manifold method，the shapes of the finite covers can be selected more easily. The finite covers and the partition of unity functions are formed by using the influence domains of a series of nodes with an advantages over the mesh-based numerical manifold method. Compared with the conventional meshless methods，the test functions are not influenced by the discontinuities in the solution domain since finite cover technology is used to overcome some difficulties inherented in the conventional meshless methods. In this paper，the meshless manifold method (MMM) is applied to analyze crack growth in rock samples. The weak solution of the partial differential equation for elasticity are derived using the method of weighted residuals (MWR). Finally，a problem with crack growth under complex stress state is solved with the MMM，the numerical results agree well with the test data，and the validity and accuracy of the MMM are demonstrated.

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APPLICATION OF 3D COUPLING MODEL OF SEEPAGE AND STRESS FOR SIMULATING DEEP FOUNDATION FITS DEWATERING

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2005, 24 (07): -1196 doi:
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Based on a literature survey，the application of coupling model of seepage and stress in rock and soil masses for simulating deep excavation dewatering is studied. Dewatering engineering of the passage under street of the Zhongshan public square is taken as an example and 3D finite element method is used to simulate the dewatering case. Through the 3D finite element analysis，the three-dimension numerical simulation method can be applied to study impervious curtain，anisotropy and pressurization—pressure that is hard to solve in practical engineering conditions. Therefore，numerical simulation technique is useful in dewatering excavation and ground settlement computation.

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A VISUAL CALCULATION ANALYSIS AND EVALUATION SYSTEM FOR MINING INDUCED SURFACE SUBSIDENCE

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2005, 24 (07): -1202 doi:
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A model for the analysis of subsidence is established to evaluate the ground distortion by using survey data at multiple points，calculation method for subsidence in general terrain conditions，surface deformation in mountain areas，and surface subsidence induced by trip mining，in computer-aided visualization-calculation system. The system primarily makes use of data conversion and transfer between softwares. The system can be used to determine the numerical value of the subsidence along a subsidence basin's alignment or inclination. As well as movement and deformation at any points of the basin area induced by mining. It can be applied to resources and environmental evaluations.

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APPLICATION OF IMPACT COMPACTION TECHNOLOGY IN HIGHWAY EMBANKMENT OF COLLAPSIABLE LOESS SOILS

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2005, 24 (07): -1207 doi:
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Based on a case of a highway embankment on collapsible loess ground，an impact compaction technology for collapsible loess ground is developed. During the process of compaction，the elastic modulus，compaction degree，collapsibility，settlement and other parameters of the soil are measured and the depth of impact compaction is comprehensively studied. The results of experiment indicate that the elastic modulus and compaction degree increase and the collapsibility and settlement decrease with impact compaction，and impact compaction is effective in improving the quality of embankment and reducing the settlement after construction.

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EXPERIMENTAL STUDY ON MEASURING TRANSIENT VERTICAL DISPLACEMENT FOR THE BLASTING MODELS

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2005, 24 (07): -1211 doi:
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An optical path of a new holographic interferometry technique is developed to measure and represent vertical displacement (vertical amplitude) fringe patterns acquired at different times in one blast. The displacement variations with line charges is studied at different cross sections of the blast region. The test data show that extreme values of vertical displacement，which is caused by P wave，along the perpendicular line of the line charge middle point is three times more than that of other sections in the full field after the detonation. In addition，the extreme displacement values in other directions are caused by Rayleigh wave. The displacement pattern along the axis of the line charge shows an obvious end-effect. The technique represents an important development in analysis of blast induced displacement fields.

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A GENERAL SLICE METHOD FOR DETERMINATION OF FACTORS OF SAFETY BASED ON FORCE EQUILIBRIUM

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2005, 24 (07): -1216 doi:
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For a general slice，force equilibrium equations are developed，and the recurrence equation of inter-slice force and the general formulation based on force equilibrium to solve the factor of safety are established. Hence，the general slice method based on force equilibrium to solve the factor of safety is developed. The vertical slice method based on force equilibrium to solve the factor of safety is a special case of this method. Analyzing the applicability of Sarma¢s method，a new inter-slice shear force equation is presented based on the compatible relationship among slices displacements. It clarifies the relationship between the inter-slice shear forces and slip surface geometry，and indicates that the reduction factor for shear strength along inter-slice boundaries varies from one boundary to the next，depending on the geometry of the slices and the slip surface. A non-rigorous method of general slice can be developed based on the proposed new inter-slice shear force equation. It assumes that the reduction factors for shear strength along inter-slice boundaries are different from that for shear strength along the slip surface. An example analysis indicates that the proposed new method is better than the Sarma¢s method，and leads to more reasonable values of safety factor. Even if the shape of slice is varied，the proposed new method can also give consistent values of safety factors and ensure that the iteration is stably convergent.

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MATHEMATICAL MODEL AND ANALYSIS ON THE RELATION BETWEEN PRESSURE AND SPEED OF COLLAPSE DURING COLLAPSE OF LOESS

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2005, 24 (07): -1222 doi:
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On the basis of energy conservation during the collapsible process of loess，a relation between pressure and collapse speed during collapse of loess was built. The model parameters and the curves of the relation were obtained by experiment. Based on the model and the curve，the obtained conclusions are：the higher pressure is，the higher collapsible speed is；the larger quantity of collapse is，the larger collapse pressure of origination is，and the collapsible speed has the character of salutation.

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ANALYSIS OF HYDRAULIC FRACTURING IN HYDRAULIC TUNNELS UNDER HIGH WATER PRESSURE

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2005, 24 (07): -1226 doi:
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The previous on hydraulic fracturing generally assume that tensile cracking is the essential mode of hydraulic fracturing in rocks. In reality，however，the mode of fracturing is combined with compression and shearing，as observed in many rock engineerings. In this paper，the effect of hydraulic fracturing on deep-lying hydraulic tunnels under high water pressure is studied on the principles of fracture mechanics. Firstly，the analysis method of stress intensity factor of crack of model I in many complex conditions in the surrounding rock masses of tunnels is presented. Then，the criteria of hydraulic fracturing of different tensile cracks are discussed. The mechanism and formula for stress intensity factor are put forward. Finally，by using the above theory，the hydraulic fracturing analysis of under-lying hydraulic tunnels of a hydropower project is performed，which shows that the method presented is reliable.

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BACK-ANALYSIS OF VISCO-ELASTIC PARAMETERS OF FILLING MATERIALS AND SETTLEMENT PREDICTION FOR HIGH-FILLED EMBANKMENT

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2005, 24 (07): -1229 doi:
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Settlement after construction is one primary problem of high-filled embankment. In this paper a method of prediction for settlement after construction was developed. A general Kelvin model was adopted to depict constitutive relationship of filling material. The bottleneck of the problem is how to obtain reliable material parameters for numerical calculations. Based on field monitoring data，back analysis approach using a 3D FEM method，an orthogonal numerical experiment，and a regression and optimization analysis was conducted to calculate the visco-elastic parameters. With these calibrated parameters，the settlement after construction of a 37 m high-filled highway embankment was predicted. The results show higher accuracy and good agreement with monitoring data. The method can be used to predict settlement after construction of high-filled embankment.

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SWELLING DEFORMATION AND CALCULATION METHODS OF COMPACTED EXPANSIVE SOIL

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2005, 24 (07): -1236 doi:
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With compacted expansive soil in Ankang city of Shanxi province，by a series of swelling capacity laboratory tests with different initial dry densities，moisture contents and pressures，the characteristics of swelling deformation with the above three parameters were found. The calculation methods of swelling capacity of compacted expansive soils，which can fulfil the accuracy requirements of engineering and take into account the coupling effects between initial dry density，initial moisture content and pressure，are summarized. The correctness of the pattern has been confirmed too. In engineering，the pattern can be utilized to calculate swelling deformation of compacted expansive soil，which can have any initial dry density，initial moisture content and pressure，with several swelling capacity tests to obtain the parameters.

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EXPERIMENTAL STUDY OF CLAY HARDENING GROUTS FOR ROADBED REINFORCEMENTS

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2005, 24 (07): -1244 doi:
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Clay hardening grouts is much superior to others when it is applied for roadbed enforcements in karst areas, with advantages such as its lower construction costs，simple and practical technology，good properties for intercepting groundwater seepage，and anti-seismic capability. In this paper，a series of grouting simulating tests show that it is feasible to reinforce roadbed horizontally in karst areas. The corresponding formula for making this grouts is obtained. For example，clay hardening grouting is done through seepage in rocks and its unconfined compressive strength (with samples cured up to 28 days) is 0.928 MPa. Its optimum prescription is made up of 5～15% cement，1～5% water glass，1～3% special hardening agent and viscosity of mud is above 30 s. Through its practical applications in Luozhan railway line，a good economic and technically effective technique has been achieved.

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STUDY ON THE HORIZONTAL DEFORMATION OF REINFORCED RETAINING WALLS OF SOILS

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2005, 24 (07): -1248 doi:
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A new method of calculating the horizontal deformation of the reinforced retaining walls is proposed. Assuming that the reinforced soil retaining wall acts as a coherent block，just like the situation of a conventional retaining wall under the horizontal earth pressure backfill material. The reinforced soil retaining wall is taken as an equivalent anisotropic elastic medium and all the elastic properties are derived. During calculating the horizontal deformation of the reinforced soil retaining wall，the reinforced soil block as a cantilever beam is assumed. The horizontal deformation of the cantilever beam is calculated for pure bend and pure shear modes. The design method is proved to be correct，as compared with testing data.

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AN EXPERIMENTAL STUDY ON STEEL FIBER REINFORCED HIGH STRENGTH CONCRETE SHAFT LINING IN DEEP ALLUVIUM

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2005, 24 (07): -1253 doi:
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Aiming at the difficult problem of reinforcement for coal mine shafts in the deep alluvium of 550～700 m，the steel fiber reinforced high strength concrete shaft lining is proposed. Through model experiments，the characteristics of stress and strength of the steel fiber reinforced high strength concrete shaft lining are studied. The results of test indicate that under same conditions，employing steel fiber reinforced high strength concrete can considerably increase the strength of the shaft lining，and the steel fiber reinforced high strength concrete shaft lining is of better plastic characteristic. At the end，an equation for calculating the ultimate bearing capacity of the steel fiber reinforced high strength concrete shaft lining is given on the basis of the theoretical research and experimental results. The studied results provide a design basis for engineering practice of shaft lining structure.

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A METHOD FOR COMPOSITE FACING OF COMPOSITE SOIL NAILING

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2005, 24 (07): -1259 doi:
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The composite facing，composed of concrete and waterproof wall，is an important component of the composite soil nailing system and plays a great role in determination of bearing loads and tensile forces of the soil nails. It’s necessary to design the composite facing before construction. For facing design, a model for a combination of soil nails with waterproof cement-soil mixing pile wall，were developed by using the theory of elastic foundation beam. The infinite-length elastic foundation beam models of the composite facing were established. In order to simplify calculations，a kinematics displacement method was proposed to calculate the internal forces in vertical cross sections of the composite facing and the calculation formulas were derived from different situations. The technique was applied to determine the strength of some cross sections from engineering practice. The calculation results indicate：(1) the internal forces of facing in vertical cross-sections will be a control factor of design，and (2) the tensile strength of cement-soil wall will govern strength of the facing. The proposed kinematical limit analysis methods are proved to be a useful technique for design and analysis of internal forces of the composite facing.

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MEASURING THE LOAD-TRANSFER FUNCTIONS OF PILES BY USING SLIDING MICROMETERS

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2005, 24 (07): -1267 doi:
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The theory and measuring method of load-transfer function of piles are introduced. With a test-pile as a sample and using sliding micrometer，the details in test and calculation processes of load-transfer functions are introduced.

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尤春安博士论文摘要

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2005, 24 (07): -1272 doi:
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尤春安博士论文摘要

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李元海博士论文摘要

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2005, 24 (07): -1273 doi:
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