含两组交叉贯通节理岩体的强度及破坏特征分析

天然岩体中常含有多组相互交叉的贯通节理，它们的存在极大地削弱了岩体的力学性质。为了研究含两组交叉贯通节理岩体的强度及破坏特征，基于弹塑性数值流形方法，对不同应力状态下，节理倾角和节理间距不同的岩体压缩试验进行数值模拟。结果表明：岩体强度随节理倾角的变化曲线呈现出多波峰、多波谷特点，岩体强度随节理间距变化曲线符合负指数函数形式。根据节理状态，两组节理岩体的破坏模式可以分为3种：岩块破坏、沿一组节理滑移和沿两组节理滑移。两组节理均会影响岩体强度，一组起主要作用，另一组起次要作用，并且节理组之间存在相互影响。通过对数值计算结果进行回归分析，基于一组节理岩体强度预测模型，量化节理组之间的相互影响，提出适用于含两组交叉贯通节理岩体的强度预测模型。模型形式简单，使用方便，可为实际工程中正确评估岩体强度提供指导性意见。

Analysis of strength and failure characteristics of rock mass with two sets of cross-persistent joints

Natural rock mass usually contains multiple sets of cross-persistent joints, which greatly weakens its mechanical properties. This study aims to investigate the strength and failure characteristics of rock mass with two sets of cross-persistent joints. Under different confining pressures, compression tests are conducted at various inclination angles and spacing values of joints, respectively. Then obtained results are further stimulated by the elastoplastic numerical manifold method. The results show that the variation of strength with the joint inclination exhibits the multi-crest and multi-trough characteristics. The variation of strength with joint spacing confirms to a negative exponential function. According to the joint states, the failure modes of rock mass can be divided into three kinds, i.e., failure of rock block, slipping along a set of joints and slipping along two sets of joints. It is found that both sets of joints affected the strength of rock mass to certain degrees. Moreover, there is an interaction between these two sets of joints. Through the regression analysis of the simulation results, a new strength prediction model is established for rock mass with two sets of cross-persistent joints. The model is based on the strength prediction model of rock mass with one set of joints and the quantification of the interaction between two sets. The model is simple in form and easy to use, which can provide a guideline for evaluating the strength and failure characteristics of rock mass in practical engineering.