层状复合岩体的改进Hoek-Brown强度准则研究

Modified Hoek-Brown strength criterion for layered composite rock mass

Hoek-Brown强度准则是岩土工程领域应用最为广泛的强度准则之一,但其最初只适用于各向同性岩体。通过将层状复合岩体考虑为横观各向同性材料,引入各向异性状态参数(被定义为材料微观结构偏张量与标准化偏应力张量之间的联合不变量),并将该参数与Hoek-Brown强度准则耦合,建立了层状复合岩体的强度准则。结合干燥和饱和状态下的千枚岩、板岩和沉积石英岩的三轴试验结果对计算结果进行验证,结果表明改进的Hoek-Brown准则能较好地预测层状复合岩体的破坏强度。

Hoek-Brown strength criterion is one of the most widely used strength criteria in the field of geotechnical engineering,however it is initially developed for isotropy rock mass. By considering the layered rock mass as a transversal isotropic material,anisotropic state scalar parameter is introduced,which is a joint invariant including deviatoric microstructure fabric tensor and a normalized deviatoric stress tensor. So,a modified Hoek-Brown strength criterion was developed by coupling the anisotropic state scalar parameter with the Hoek-Brown strength criterion. It was verified by Phyllite,Slate and Orthoquartzite triaxial compressive testing data under dry and saturated states. The results show that the modified Hoek-Brown strength criterion can be used to predict the failure strength of layered rock mass.