三维大理岩弹塑性损伤及细观破坏过程数值模拟  

3D NUMERICAL SIMULATION OF ELASTOPLASTIC DAMAGE AND MICROFRACTURING PROCESS OF MARBLE SAMPLES

作　　者：赵吉坤[1] 张子明[2] 

机构地区：[1]南京农业大学工学院,江苏南京210031 [2]河海大学工程力学系,江苏南京210098

出　　处：《岩石力学与工程学报》2008年第3期487-494,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(50379004)

摘　　要：目前对于岩石细观破坏的研究取得了一些进展,但在许多工程领域不能简单地采用弹性损伤模型分析,而要考虑岩石细观局部塑性变形对岩体强度和稳定性的重要影响。因此,基于应变空间理论导出弹塑性损伤细观模型,提出破坏单元网格消去法模拟裂纹扩展,程序自动删除损伤度为1的细观单元,使该单元在下一步计算中失去作用,利用高性能并行计算实现岩石三维破裂过程的数值模拟。对大理岩三点弯曲试样I型及I–II复合型裂纹的破坏过程进行数值模拟,研究裂纹穿晶和绕晶破坏问题,给出裂纹萌生、扩展过程及破坏形态,分析细观非均匀性对岩石宏观破裂力学行为的影响。计算结果表明,考虑岩石细观局部塑性变形时的岩体稳定性要大于不考虑局部塑性时的稳定性,仿真试验和物理试验吻合较好,由此说明所提出的岩石弹塑性损伤破坏模型的正确性和有效性;裂纹尖端晶体强度影响穿晶和绕晶的破坏模式;破坏单元网格消去法解决有限元模拟裂纹扩展的难题,给出的模型和方法可付诸于实践。In recent years, some progresses are achieved in the research of rock mesoscopic failure, but elastic damage model cannot be adopted simply in many practical projects. Therefore, most important influences of mesoscopic local plastic deformation of rock on strength and stability of rock mass should be considered. An elastoplastic damage mesoscopic model is deduced based on the theory of strain space. The failure elements deleting method is put forward to simulate the crack propagation. If the degree of damage elements equals 1, the code deletes these elements automatically in order to explicitly show how cracks propagate in rock. High-performance parallel calculation is adopted to realize 3D numerical simulation of rock fracture process. The failure processes of marble three-point bending specimens with modes Ⅰ and Ⅰ- Ⅱ cracks are numerically simulated. By setting crystal in crack-tip, transgranular fracture and intergranular fracture are studied. The initiation and propagation of cracks and the failure shapes of the specimens are given. The influence of mesoscopic heterogeneity on rock macroscopic failure mechanical behaviors is analyzed. The calculation results show that the rock mass stability considering mesoscopic local plastic deformation is better than that without consideration of local plasticity. The results of simulation and physical tests accord each other well, which illuminates the validity of the elastoplastic damage failure model. Failure pattern of transgranular fracture and intergranular fracture depends on the intension of crystal. The failure elements deleting method solves the difficult problem of FEM to simulate propagation. The model and method may be valid in practical projects.

关 键 词：岩石力学 数值模拟 弹塑性损伤 大理岩 细观破裂过程 

分 类 号：TU45[建筑科学—岩土工程]