A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/s...A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/softening constitutive model based on the unified strength theory(UST) were used to simulate both the consolidated-undrained(CU) triaxial and the consolidated-drained(CD) true triaxial tests. Based on the results of the true triaxial tests simulation, the effect of the intermediate principal stress on the strength of soft rock was investigated. Finally, an example of an axial compression test for a hard rock pillar with a soft rock interlayer was analyzed using the two-dimensional finite difference code FLAC. The CD true triaxial test simulations for diatomaceous soft rock suggest the peak and residual strengths increase by 30% when the effect of the intermediate principal stress is taken into account. The axial compression for a rock pillar indicated the peak and residual strengths increase six-fold when the soft rock interlayer approached the vertical and the effect of the intermediate principal stress is taken into account.展开更多
This paper presents a stochastic fatigue damage model for concrete subjected to complex stress states.A constitutive framework considering the tensile and shear damage mechanisms and elastic and plastic energy dissipa...This paper presents a stochastic fatigue damage model for concrete subjected to complex stress states.A constitutive framework considering the tensile and shear damage mechanisms and elastic and plastic energy dissipations is employed.The damage law is established through a multiscale analysis of the damage evolution mechanism.Validation results against test data show that the model can effectively predict the static strength,stress-strain curve,fatigue life,and scattering range of concrete under various multidimensional loading scenarios.展开更多
为研究高土石坝坝体内土体单元在复杂应力状态下的渗透性能,在中型三轴仪上对同一土料场3种不同级配土料进行三轴渗透试验。试验围压分为5级(100 k Pa、400 k Pa、800 k Pa、1 200k Pa和2 000 k Pa),每级围压下分4种应力水平(0、0.2、0....为研究高土石坝坝体内土体单元在复杂应力状态下的渗透性能,在中型三轴仪上对同一土料场3种不同级配土料进行三轴渗透试验。试验围压分为5级(100 k Pa、400 k Pa、800 k Pa、1 200k Pa和2 000 k Pa),每级围压下分4种应力水平(0、0.2、0.4和0.8),当试样在初始应力状态下变形基本稳定后,采用常水头法测试试样的渗透系数。试验结果表明:级配是影响渗透系数的重要因素,相同应力条件下土料粉粒和黏粒含量越高,渗透系数越小;随围压和应力水平的提高,土料的渗透系数逐渐降低;粉粒和黏粒含量越低、大颗粒含量越高,围压对土料渗透系数的影响越显著;对于不同级配相同密实度试样,应力水平对渗透系数的影响程度基本一致。在分析渗透系数随围压和应力水平变化规律的基础上,建立了能描述复杂应力状态条件下土体渗透系数的经验公式。展开更多
基金Projects(41172276,51279155)supported by the National Natural Science Foundation of ChinaProjects(106-00X101,106-5X1205)supported by the Central Financial Funds for the Development of Characteristic Key Disciplines in Local University,China
文摘A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/softening constitutive model based on the unified strength theory(UST) were used to simulate both the consolidated-undrained(CU) triaxial and the consolidated-drained(CD) true triaxial tests. Based on the results of the true triaxial tests simulation, the effect of the intermediate principal stress on the strength of soft rock was investigated. Finally, an example of an axial compression test for a hard rock pillar with a soft rock interlayer was analyzed using the two-dimensional finite difference code FLAC. The CD true triaxial test simulations for diatomaceous soft rock suggest the peak and residual strengths increase by 30% when the effect of the intermediate principal stress is taken into account. The axial compression for a rock pillar indicated the peak and residual strengths increase six-fold when the soft rock interlayer approached the vertical and the effect of the intermediate principal stress is taken into account.
基金supported by the National Natural Science Foundation of China (Grant No. 51538010)the Shanghai Municipal Education Commission (Grant No. 02102360152)。
文摘This paper presents a stochastic fatigue damage model for concrete subjected to complex stress states.A constitutive framework considering the tensile and shear damage mechanisms and elastic and plastic energy dissipations is employed.The damage law is established through a multiscale analysis of the damage evolution mechanism.Validation results against test data show that the model can effectively predict the static strength,stress-strain curve,fatigue life,and scattering range of concrete under various multidimensional loading scenarios.
文摘为研究高土石坝坝体内土体单元在复杂应力状态下的渗透性能,在中型三轴仪上对同一土料场3种不同级配土料进行三轴渗透试验。试验围压分为5级(100 k Pa、400 k Pa、800 k Pa、1 200k Pa和2 000 k Pa),每级围压下分4种应力水平(0、0.2、0.4和0.8),当试样在初始应力状态下变形基本稳定后,采用常水头法测试试样的渗透系数。试验结果表明:级配是影响渗透系数的重要因素,相同应力条件下土料粉粒和黏粒含量越高,渗透系数越小;随围压和应力水平的提高,土料的渗透系数逐渐降低;粉粒和黏粒含量越低、大颗粒含量越高,围压对土料渗透系数的影响越显著;对于不同级配相同密实度试样,应力水平对渗透系数的影响程度基本一致。在分析渗透系数随围压和应力水平变化规律的基础上,建立了能描述复杂应力状态条件下土体渗透系数的经验公式。
