非贯通节理岩体多层结构模型研究Ⅰ:理论部分

Study on Hierarchical Model of Non-persistent Joint Rock Mass Ⅰ:Theory

岩体的力学性状与其结构面分布及特性有关,对于非贯通节理岩体,当节理定向排列,特别是岩桥长度远小于节理长度时,一般发生共面剪切破坏。针对压剪荷载下非贯通节理岩体,将共面节理及其间岩桥构成的剖面称为等代结构面,结合断裂力学方法,研究了非贯通节理岩体多层结构模型。模型包括弹性变形、滑移、开裂直至贯通等阶段。等代结构面剪切强度由节理与岩桥2部分组成,其中,节理强度表现为基本摩擦角与粗糙角,岩桥强度表现为等效粘聚力。节理贯通时,退化为Zienkiewicz节理岩体模型。

The mechanical behaviors of rock mass are related to the distribution of structure surface.For the non-persisent joint,the shear failure usually occurred along the co-plane when the joint is in aligned form,especially the length of rock bridge is far smaller than the joint.As to the non persistent joint rock mass loaded with compressing and shearing,the proflie constituted by joint and rock bridge is defined as equivalent structure surface,in combination with fracture mechanics theory,the hierarchical model of non-persistent rock mass is built.The model considers different change stages such as elastic,sliding and cracking.The shear strength of equivalent structure surface is made up of the strentgth of joint and rock bridge,among them,the strength of joint is represented by the basic friction angle and rough angle,the strength of rock bridge is represented by equivalent cohesion.when the joint become persistent,the model degenrates to the Zienkiewicz model.