岩石中三维单裂隙扩展过程的试验研究和数值模拟

Experimental study and numerical simulation of propagation and coalescence process of a single three-dimensional flaw in rocks

采用一种新型的透明性和脆性度良好的非饱和树脂材料,制作了一组含有不同倾角椭圆形三维内置单裂隙的试样。研究了单轴压缩条件下单裂隙的扩展与贯通过程,分析探讨其产生的条件和机理。试验结果表明:三维单裂隙试件破坏过程大致经历4个阶段。三维单裂隙的断裂比二维断裂复杂得多,产生多种不同形态的裂纹,如鱼鳍状裂纹、花瓣形裂纹等。在FLAC^(3D)软件框架内还建立了一种新的弹脆性破坏本构关系和分析法,并采用超细单元划分法建模,用以模拟三维裂隙扩展。数值模拟结果与本文和前人的三维裂隙试验对照,相符程度均良好,表明了新的数值模拟方法的有效性。当推广到双轴压缩试验模拟时,也与前人相关试验结果有很好的一致性。

A team of specimens containing different dip angles of a single three -dimensional(3D) crack were made by using a new type of unsaturated transparent and rock-like resin.The propagation and coalescence process of a single 3 D crack under uniaxial compression were studied,and its production conditions and mechanism were further analyzed. It' s shown by the test results that the failure process of specimens containing a single 3D crack can be generally divided into four stages.The fracture of a single 3D crack,which produces a variety of different forms of cracks,is much more complex than the fracture of a single 2D crack.In this paper,by employing the analysis software of FLAC^(3D) and establishing a new elastic-brittle constitutive relation,as well as using superfine unit division,the propagation process of a single 3D crack were simulated and studied.The numerical results match well with the testing results in this paper and that obtained by former scholars,which suggests the effectiveness of the new numerical simulation method.