1982 Vol. 4 No. 3
1982, 4(3): 1-10.
Abstract：
In view of the differences between microscopic and macroscopic liquefaction of soils, and many unsolved problems in taking undisturbed sand samples, running laboratory testings etc., the author tries to explore some new ways for evaluating liquefaction potential by macroscopic approach to the occurance criteria and development of soil liquefaction. This paper presents some results of such work which can be used in association with the laboratory analysis so as to make further reliable assessment of liquefaction potential and its seismic effect.
In view of the differences between microscopic and macroscopic liquefaction of soils, and many unsolved problems in taking undisturbed sand samples, running laboratory testings etc., the author tries to explore some new ways for evaluating liquefaction potential by macroscopic approach to the occurance criteria and development of soil liquefaction. This paper presents some results of such work which can be used in association with the laboratory analysis so as to make further reliable assessment of liquefaction potential and its seismic effect.
Abstract：
This paper is based upon the results of static load tests on 14 uplift （D=45, 60cm; L = 4.212m） and 2 compression （D=60cm, L = 9, 12m） prototype piles in silty clay and silts. Influences of the variation of pile length on ultimate uplift skin friction and development of shaft resistance in uplift and compression versus pile top displacement are discussed.The ratios of skin friction in uplift to that in compression are presented and found to be varying with depths of penetration.Displacement patterns of ground surface around piles of different penetration during uplift are observed.A group efficiency of 0.9 for 2-piles groups with 2D spacing is also suggested.
This paper is based upon the results of static load tests on 14 uplift （D=45, 60cm; L = 4.212m） and 2 compression （D=60cm, L = 9, 12m） prototype piles in silty clay and silts. Influences of the variation of pile length on ultimate uplift skin friction and development of shaft resistance in uplift and compression versus pile top displacement are discussed.The ratios of skin friction in uplift to that in compression are presented and found to be varying with depths of penetration.Displacement patterns of ground surface around piles of different penetration during uplift are observed.A group efficiency of 0.9 for 2-piles groups with 2D spacing is also suggested.
1982, 4(3): 27-42.
Abstract：
In this paper, single pile lateral load capacity has been analyzed, based upon test results on four cast-in-situ concrete piles installed with "jetting and suction" drill, different in length, diameter and percentage of reinforcement.Criteria for determining single pile critical cracking load have been investigated. For three of the four piles were instrumented, and bending moments on different sections have been figured from measured REBAR stresses on these sections; such bending moments figured from REBAR stresses have been compared with theoretical values of bending moments computed from four methods currently accepted at home and abroad. Values of soil moduli have been back-figured from measured pile-head lateral movements at ground level, and a tentative rule for variation of soil moduli as a function of pile-head displacement has been suggested. Computed pile-head angular displacements have been compared with values measured in the field. Finally, influences of variation in pile length, diameter and percentage of reinforcement on the lateral load capacity for single-piles are preliminarily studied.
In this paper, single pile lateral load capacity has been analyzed, based upon test results on four cast-in-situ concrete piles installed with "jetting and suction" drill, different in length, diameter and percentage of reinforcement.Criteria for determining single pile critical cracking load have been investigated. For three of the four piles were instrumented, and bending moments on different sections have been figured from measured REBAR stresses on these sections; such bending moments figured from REBAR stresses have been compared with theoretical values of bending moments computed from four methods currently accepted at home and abroad. Values of soil moduli have been back-figured from measured pile-head lateral movements at ground level, and a tentative rule for variation of soil moduli as a function of pile-head displacement has been suggested. Computed pile-head angular displacements have been compared with values measured in the field. Finally, influences of variation in pile length, diameter and percentage of reinforcement on the lateral load capacity for single-piles are preliminarily studied.
Abstract：
A simple and convenient method known as the discounted well-diameter method to think of the effect of drain well resistance on the rate of consolidation of soft clays for free strain is presented by the writer of this paper. The method makes it possible that a drain well having some resistance to flow of the expelled water can be considered as an equivalent ideal well for which the effect of the well resistance is ignored. The difference between the vertical and horizontal permeabilities can be considered by means of the method proposed. Results obtained by the discounted well-diameter method are compared with the solution proposed by Yoshikuni et al, 1974, which is restricted to that the radial consolidation coefficient equals to the vertical one.
A simple and convenient method known as the discounted well-diameter method to think of the effect of drain well resistance on the rate of consolidation of soft clays for free strain is presented by the writer of this paper. The method makes it possible that a drain well having some resistance to flow of the expelled water can be considered as an equivalent ideal well for which the effect of the well resistance is ignored. The difference between the vertical and horizontal permeabilities can be considered by means of the method proposed. Results obtained by the discounted well-diameter method are compared with the solution proposed by Yoshikuni et al, 1974, which is restricted to that the radial consolidation coefficient equals to the vertical one.
Abstract：
This paper suggests a finite element analysis method of the multilayer pavement with materials of nonlinearity. The triaxial test has been adopted to determine the nonlinear parameters. In the methods of nonlinear analysis, along with the normal variable stiffness methods, the improved BFGS method is used. Through calculations it is found that this method is more applicable than the variable stiffness method.In order to verify the correctness of the result of the nonlinear analysis, we have compared them with the measuring deflection value of the experimental pavement in full scale and at the same time with the results gained by solution of linear elastic theory.
This paper suggests a finite element analysis method of the multilayer pavement with materials of nonlinearity. The triaxial test has been adopted to determine the nonlinear parameters. In the methods of nonlinear analysis, along with the normal variable stiffness methods, the improved BFGS method is used. Through calculations it is found that this method is more applicable than the variable stiffness method.In order to verify the correctness of the result of the nonlinear analysis, we have compared them with the measuring deflection value of the experimental pavement in full scale and at the same time with the results gained by solution of linear elastic theory.
Abstract：
The results of laboratory tests showed that the apparent preconsolidation pressure of Shanghai clay is higher than the effective overburden pressure. It's effects on the behaviour of soils are discussed based on the principle of critical state in this paper. The normal consolidation line, the critical state line and the strength envelope line are determined from the laboratory tests, and equations of these lines are given. In accordance with the variations of consolidation, shear strength, stress-strain relationships and pore pressure, it is concluded that Shanghai clay behaviours indicated as being slightly overconsolidated. The pc-effect should be considered in settlement calculatoins and stability analysis to improve the design methods.
The results of laboratory tests showed that the apparent preconsolidation pressure of Shanghai clay is higher than the effective overburden pressure. It's effects on the behaviour of soils are discussed based on the principle of critical state in this paper. The normal consolidation line, the critical state line and the strength envelope line are determined from the laboratory tests, and equations of these lines are given. In accordance with the variations of consolidation, shear strength, stress-strain relationships and pore pressure, it is concluded that Shanghai clay behaviours indicated as being slightly overconsolidated. The pc-effect should be considered in settlement calculatoins and stability analysis to improve the design methods.
Abstract：
In this papar, the rock behavior before yielding is analyzed by using the theories of continuum mechanics. The nonlinearly elastic constitutive equation of rock medium is derived and compared satisfactorily with the available experimental data. Moreover, the substitution of linearly elastic hypothesis used in the conventional cap model with the nonlinearly elastic one leads to develop a new nonlinearly elastic-hardening plastic cap model as presented herein.
In this papar, the rock behavior before yielding is analyzed by using the theories of continuum mechanics. The nonlinearly elastic constitutive equation of rock medium is derived and compared satisfactorily with the available experimental data. Moreover, the substitution of linearly elastic hypothesis used in the conventional cap model with the nonlinearly elastic one leads to develop a new nonlinearly elastic-hardening plastic cap model as presented herein.
Abstract：
One of the points in our studying chemical grouting is to use organic compounds as bedrock consolidation grouting materials. This article describes how after consolidation treatment of moderately weathered quartzdiorite zone at a dam site by the use of methacrylate chemical grouts modulus of deformation was increased from 26.3×10~4 kg/ cm2 to 47.4×10~4 kg/cm2; static elastic modulus was increased from 29.6×10~4 kg/cm2 to 57.9×10~4 kg/cm2; the speed of sound wave, Vp, from 4894 m/s to 5272 m/s; and dynamic elastic modulus from 53.4×104~ kg/cm2 to 62.4 × 10~4 kg/cm2; unit water absorption ω was reduced from 0.035 1/min to 0.012 1/min and adhesive strength of fissure was increased from O to 13.4 kg/cm2.
One of the points in our studying chemical grouting is to use organic compounds as bedrock consolidation grouting materials. This article describes how after consolidation treatment of moderately weathered quartzdiorite zone at a dam site by the use of methacrylate chemical grouts modulus of deformation was increased from 26.3×10~4 kg/ cm2 to 47.4×10~4 kg/cm2; static elastic modulus was increased from 29.6×10~4 kg/cm2 to 57.9×10~4 kg/cm2; the speed of sound wave, Vp, from 4894 m/s to 5272 m/s; and dynamic elastic modulus from 53.4×104~ kg/cm2 to 62.4 × 10~4 kg/cm2; unit water absorption ω was reduced from 0.035 1/min to 0.012 1/min and adhesive strength of fissure was increased from O to 13.4 kg/cm2.
Abstract：
In this paper, it begins with fundamental concept of seepage force and points out the questions existing in the usual method of slices for stability analysis. Then the finite element method directly applied to stability analysis of earth dams under seepage flow is proposed and the computation formulas for sliding surfaces of single arc and composite arcs are given.In order to justify this method and its computer program we have computed six actual earth dams and two model dams that had occured slope sliding with certain hydraulic condition. The results of computation have verified that those dams should be failed and the most dangerous sliding positions as well as the hydraulic conditions are almost same with that occured in actual dams. On the other side, the computation results by the usual method of slices could not completely verify what the failure in actual cases must be happen. Thus this F. E. M. has been proved that it is more reliable and simpler than others.
In this paper, it begins with fundamental concept of seepage force and points out the questions existing in the usual method of slices for stability analysis. Then the finite element method directly applied to stability analysis of earth dams under seepage flow is proposed and the computation formulas for sliding surfaces of single arc and composite arcs are given.In order to justify this method and its computer program we have computed six actual earth dams and two model dams that had occured slope sliding with certain hydraulic condition. The results of computation have verified that those dams should be failed and the most dangerous sliding positions as well as the hydraulic conditions are almost same with that occured in actual dams. On the other side, the computation results by the usual method of slices could not completely verify what the failure in actual cases must be happen. Thus this F. E. M. has been proved that it is more reliable and simpler than others.
