Numerical study on failure behavior of brittle rock specimen containing pre-existing combined flaws under different confining pressure
Numerical study on failure behavior of brittle rock specimen containing pre-existing combined flaws under different confining pressure
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DOI：
10.1016/j.acme.2015.03.005
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发表时间：
2015-09
影响因子：
4.4
通讯作者：
Shengqi Yang;Tao Xu;Lei He;H. Jing;Sen Wen;Q. Yu
中科院分区：
文献类型：
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作者：
Shengqi Yang;Tao Xu;Lei He;H. Jing;Sen Wen;Q. Yu
为了深入理解脆性岩石材料的断裂机理，利用RFPA 2D对含7种不同裂隙角的组合裂纹（2个方孔和1个预存裂隙）岩石试件进行了数值模拟。数值模拟结果与实验结果吻合较好。总结了单轴压缩条件下含组合裂纹试件的裂纹贯通行为，裂纹贯通行为与裂纹角度密切相关。原始裂纹的稳定扩展不会导致较大的声发射事件，但新裂纹的合并会导致较大的声发射事件。含复合缺陷试样的峰值强度随围压的增大而增大。根据线性Mohr-Coulomb准则，得到了含复合缺陷试件的粘聚力和内摩擦角，发现粘聚力和内摩擦角与裂隙角呈明显的非线性关系。在0 ~ 30 MPa范围内，随着围压的增加，累积声发射事件逐渐减少，这主要是由于较高围压抑制了裂隙尖端和双方形附近拉伸裂纹的萌生和扩展。
To understand deeply the fracture mechanism of brittle rock material, the rock specimen containing combined flaws (two square holes and one pre-existing fissure) with seven different fissure angles is carried out the numerical simulation by RFPA2D. Numerically simulated results show a good agreement with the experimental results. The crack coalescence behavior of specimen containing combined flaws under uniaxial compression is summarized, which is closely dependent to fissure angle. The stable propagation of original cracks does not lead to a larger AE event, but the coalescence of new cracks causes a larger AE event. The peak strength of specimen containing combined flaws increases with the confining pressure. According to the linear Mohr-Coulomb criterion, the cohesion and internal friction angle of specimen containing combined flaws are obtained, which is found to take on a distinct nonlinear relation with the fissure angle. The accumulated AE events decreases as the confining pressure increases from 0 to 30 MPa, which results mainly from the restraining of higher confining pressures on the initiation and propagation of tensile cracks at the fissure tips and nearby double squares.