A three-dimensional numerical investigation of the fracture of rock specimens containing a pre-existing surface flaw
A three-dimensional numerical investigation of the fracture of rock specimens containing a pre-existing surface flaw
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DOI：
10.1016/j.compgeo.2012.04.011
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发表时间：
2012-09
影响因子：
5.3
通讯作者：
Z. Liang;H. Xing;Shanyong Wang;David J. Williams;C. Tang
中科院分区：
文献类型：
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作者：
Z. Liang;H. Xing;Shanyong Wang;David J. Williams;C. Tang
采用并行有限元方法，在超级计算机上对两种非均质岩石的三维表面裂纹起裂和扩展进行了数值模拟。数值模拟的岩石标本含有预先存在的缺陷进行单轴压缩，直到失败。通过数值模拟再现了翼裂纹、反翼裂纹和壳状裂纹的萌生和扩展过程。数值模拟结果表明，翼裂纹和壳状裂纹的进一步扩展停止，由于其包裹（弯曲）行为在三维空间中，即使施加的载荷继续增加。岩石的非均匀性会显著影响岩石的裂纹扩展模式和单轴抗压强度峰值。此外，反翼裂纹只出现在相对不均匀的岩石，和峰值单轴抗压强度的标本被观察到依赖于预先存在的缺陷的倾斜。最后，表面裂纹扩展的机制进行了讨论的上下文中的数值模拟的反平面加载试验，其中，它被确定为模式III加载（反平面加载）不会导致模式III断裂的岩石，由于它们的高比例的单轴抗压强度，抗拉强度。这一发现可以解释现有缺陷在其自身平面上的横向生长，这是一种在实验室实验中没有观察到的现象。
Three-dimensional surface crack initiation and propagation in two kinds of heterogeneous rocks were numerically investigated via parallel finite element analysis using a supercomputer. Numerically simulated rock specimens containing a pre-existing flaw were subjected to uniaxial compression until failure. The initiation and propagation of wing cracks, anti-wing cracks, and shell-like cracks were reproduced by numerical simulations. The numerically simulated results demonstrate that the further propagation of wing cracks and shell-like cracks stop due to their wrapping (curving) behavior in three-dimensional spaces, even if the applied loads continue to increase. Furthermore, rock heterogeneity could significantly influence crack propagation patterns and the peak uniaxial compressive strengths of rock specimens. Moreover, anti-wing cracks only appeared in relatively heterogeneous rocks, and the peak uniaxial compressive strengths of the specimens were observed to depend on the inclination of the pre-existing flaw. Finally, the mechanism of surface crack propagation is discussed in the context of numerically simulated anti-plane loading tests, wherein it was identified that Mode III loading (anti-plane loading) does not lead to Mode III fracture in rocks due to their high ratio of uniaxial compressive strength to tensile strength. This finding could explain the lateral growth of an existing flaw in its own plane, which is a phenomenon that has not been observed in laboratory experiments.