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
针对深埋硬岩在多轴应力条件下的破坏特征,在笔者所在课题组工作的基础上,提出能够反映岩石在多轴应力作用下力学参数随塑性内变量的演化关系以及中间主应力和最小主应力对深埋硬岩脆延转换行为影响的岩体局部劣化模型(rock mass local ...针对深埋硬岩在多轴应力条件下的破坏特征,在笔者所在课题组工作的基础上,提出能够反映岩石在多轴应力作用下力学参数随塑性内变量的演化关系以及中间主应力和最小主应力对深埋硬岩脆延转换行为影响的岩体局部劣化模型(rock mass local deterioration model,RLDM),该模型考虑真实岩体应力状态对岩体力学行为的控制作用,并嵌入到自行开发的三维弹塑性细胞自动机软件系统中,而基于局部作用原理的细胞自动机方法能够方便地考虑岩石破坏过程中局部力学参数的动态更新。实验室尺度岩样的破坏过程模拟,较好地反映了随着围压的升高,岩石由脆性向延性转化的试验现象;工程尺度的锦屏二级水电站引水隧洞破坏行为模拟,获得的隧洞破裂模式较好地反映现场实际破坏现象,从而验证模型和模拟方法的正确性和合理性。在此基础上,以深埋硬岩为研究对象,分别考虑不同侧压力系数、不同中间主应力大小和方向,分析多轴应力对深埋硬岩破裂行为的影响,解释造成深埋硬岩隧洞复杂破裂模式的原因。结果表明,最小主应力升高使深埋隧洞的稳定性增强;深埋隧洞围岩的稳定性具有中间主应力效应及其区间性的特征。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.
文摘针对深埋硬岩在多轴应力条件下的破坏特征,在笔者所在课题组工作的基础上,提出能够反映岩石在多轴应力作用下力学参数随塑性内变量的演化关系以及中间主应力和最小主应力对深埋硬岩脆延转换行为影响的岩体局部劣化模型(rock mass local deterioration model,RLDM),该模型考虑真实岩体应力状态对岩体力学行为的控制作用,并嵌入到自行开发的三维弹塑性细胞自动机软件系统中,而基于局部作用原理的细胞自动机方法能够方便地考虑岩石破坏过程中局部力学参数的动态更新。实验室尺度岩样的破坏过程模拟,较好地反映了随着围压的升高,岩石由脆性向延性转化的试验现象;工程尺度的锦屏二级水电站引水隧洞破坏行为模拟,获得的隧洞破裂模式较好地反映现场实际破坏现象,从而验证模型和模拟方法的正确性和合理性。在此基础上,以深埋硬岩为研究对象,分别考虑不同侧压力系数、不同中间主应力大小和方向,分析多轴应力对深埋硬岩破裂行为的影响,解释造成深埋硬岩隧洞复杂破裂模式的原因。结果表明,最小主应力升高使深埋隧洞的稳定性增强;深埋隧洞围岩的稳定性具有中间主应力效应及其区间性的特征。
