岩石宏细观弹塑性损伤破坏对比研究

为了考虑岩石内细观局部塑性变形,基于应变空间理论导出岩石弹塑性损伤增量本构方程,提出了在计算程序中用破坏单元网格消去法清晰模拟裂纹扩展的方法,解决了有限元模拟裂纹的难题,分别从宏观尺度和细观尺度研究了岩石I型裂纹弹塑性损伤破坏问题。对比分析表明,宏观尺度研究I型裂纹扩展符合断裂力学理论分析;细观尺度研究岩石破坏过程能深入解释细观破坏机理,岩石宏观破坏直接与其内部的细观损伤破坏有关;三维数值模拟破坏过程比二维破坏更为复杂;大理岩偏三点弯曲梁弹塑性损伤破坏数值模拟得到的结果与试验结果较为吻合,验证了新建细观尺度模型模拟岩石破坏问题的合理性。

Comparison of macro-scale and meso-scale elasto-plastic damage failure in rocks

In order to consider local plastic deformation with a mesoscopic view in rocks,an elasto-plastic damage constitutive model based on incremental theory was deduced in strain space,and the failure elements deleting method was used to simulate crack propagation in program so as to explicitly show how the cracks extend in rocks.The elasto-plastic damage and failure problem of mode I crack was studied at macro-scale level and meso-scale level respectively.The comparison indicates that the mode I crack extending accords with the theory of fracture mechanics at macro-scale level.The study on failure process of rocks at meso-scale level can explain meso-failure mechanism.And rock's macro failure was directly connected with meso damage and failure.The rock's failure process of 3-D numerical simulation was more complicated than that of 2-D simulation.The simulated result of marble's elasto-plastic damage failure agrees well with the experimental result of three point bending beam of marble,which proves that the meso-scale level model was suitable to simulate problems of rock's failure.