水泥圆柱试件断裂破坏的数值模拟

Numerical simulation and analysis of mechanism behind fracture and failure of cement column

煤岩瓦斯动力灾害大多表现为瞬间断裂破坏,其破坏机理及过程还不十分清楚。以不同配比的水泥圆柱试件为研究对象,借助FLAC3D软件建立三维模型,对实验现象进行模拟和机理分析。结果表明:模型试件的轴向拉应力达到抗拉强度时,试件中心出现局部拉伸破坏区域,此时的围压与实验加载破断围压完全一致;继续增大围压,最大拉应力达到抗拉强度后不再增加。误差性分析证明,当σc=10σt时,模拟的临界围压与实验断裂破坏吻合最好。该结果对于研究三维岩石拉伸断裂瞬间破坏和煤岩瓦斯动力灾害瞬间断裂破坏机理有积极的意义。

The dynamic disasters of coal and gas occur in the typical form of instant fractures governed by an elusive mechanism and process. This paper introduces the simulation analysis and mechanism analysis of experimental phenomena,using different proportions of cement column specimens as the research object and drawing on a three-dimensional model developed by the aid of FLAC3 Dsoftware. Numerical simulation analysis shows that,when the axial tensile stress of model specimen reaches the tensile strength,the local tensile failure zone occurs at the center of the specimen,during which time the confining pressure is completely consistent with that of the experiment,meaning that a continued increase in the confining pressure produces no more increase in the maximum tensile stress after the stress is up to tensile strength; and the error analysis of numerical model verifies a best agreement between the critical confining pressure and the experimental fracture,when σc= 10σt. The research results are of positive significance for a better insight into the mechanism underlying both the three-dimensional rock tensile fracture instant destruction and gas dynamic disaster instant fracture.