层状岩体各向异性对裂纹断裂特性影响研究

Effect of the Anisotropy of the Layered Rock Mass on the Fracture Behaviours of Its Embedded Cracks

为探讨层状工程岩体在平行和垂直层面方向的各向异性对其中埋藏裂纹断裂特性的影响,将层状工程岩体地基模拟为半无限横观各向同性介质,用平行和垂直层面方向弹性系数的比值来表征该类岩体各向异性的程度,采用基于双横观各向同性材料基本解的对偶边界元方法,分析了该类岩体在平行和垂直层面方向上的弹性模量、剪切模量和泊松比的各向异性对正交于层面的单条矩形裂纹应力强度因子(SIF)和两条裂纹间相互作用的影响规律。数值计算结果表明:平行层面方向的裂尖SIF值随垂直层面方向的弹性模量和剪切模量的减小而减小,垂直层面方向的裂尖SIF值变化规律正好相反。泊松比的各向异性对裂尖SIF值和两条裂纹间的相互作用均基本无影响。

The effect of anisotropy of the layered rock on the fracture behaviours of the embedded cracks is analyzed by using dual boundary element method. The layered rock foundation is modeled as transversely isotropic materials occupying semi-infinite extent. The anisotropy of the rock is expressed by ratio of elastic coefficients in directions perpendicular and parallel to the layer. By numerical calculation the effect of the anisotropy of elastic modulus,shear modulus and poisson's ratio of the rock on the SIF values of a single rectangular crack and the interaction between two coplanar cracks is obtained. The numerical results show that the SIF values for the crack tip parallel to the isotropic plane decrease with the decrease of the elastic modulus and shear modulus in a direction normal to the isotropic plane and those for the crack tip normal to the isotropic plane are contrary. The anisotropy of Poisson's ratio has almost no effect on the SIF values and the interaction between the two coplanar cracks.