含2条断续裂隙试件直接拉伸下的颗粒流模拟

Particle Flow Analysis of Rock with Two Non-persistent Flaw in Direct Tension

采用颗粒流程序PFC构建了试件直接拉伸模型,模拟了含2条断续裂隙试件的直接拉伸试验,通过完整试件的模拟结果与室内试验结果的对比,验证了细观参数的准确性和可靠性,同时分析了裂隙倾角和岩桥倾角对抗拉强度和裂纹扩展的影响。研究表明:在直接拉伸情况下,含2条断续裂隙试件以萌生次生倾斜反翼裂纹为主,少量次生共面裂纹和翼裂纹;岩桥倾角和裂隙倾角均较小时,次生共面裂纹与原始裂隙之间发生搭接、贯通,随着岩桥倾角和裂隙倾角的加大,次生倾斜反翼裂纹扩展使试件断裂;裂纹扩展的方向与最大拉应力的方向基本保持垂直;岩桥倾角对于试件的抗拉强度和起裂应力影响不大;裂隙倾角对于试件抗拉强度和起裂应力影响明显,裂隙倾角越大,试件抗拉强度和起裂应力越大。

The direct tensile model of specimen was constructed by particle flow software PFC.The direct tensile test of two non-persistent flaw specimens was simulated.The comparison between the simulation results of the complete specimen and the indoor test results confirms the accuracy and reliability of the parameters,and the influence of the flaw and the rock bridge of the inclination on the tensile strength and crack propagation are also analyzed.The results show that under direct tension,two non-persistent flaw specimens are mainly composed of oblique secondary crack,and a small number of quasi-coplanar secondary cracks and wing cracks.When the inclination of the rock bridge and the cracks are small,the direction of the crack propagation is basically perpendicular to the direction of the maximum tensile stress.The direction of the cracks is the same as the direction of the maximum tensile stress.The inclination angle of the rock bridge has little effect on the tensile strength and the initiation stress.There is obvious influence of the crack angle on the tensile strength and the initiation stress of the specimen.The tensile strength and the initiation stress increase with the increase of the inclination angle of the flaw.