Study on elastoplastic parameters based on Mohr-Coulomb Criterion and its application

摘要

岩石力学实验是获取岩石物理力学性质参数的重要手段,应用弹塑性理论能够研究岩石变形过程中存在的塑性变形及其对岩石材料力学性质的影响.本文认为开展三轴岩石力学试验,利用Mohr-Coulomb准则,计算与岩石屈服强度、峰值强度和残余强度相对应的内聚力和内摩擦角,分析研究内聚力和内摩擦角随内变量的变化规律是一条探索岩石弹塑性力学性质的重要途径.基于各向同性软(硬)化的基本假设,对北京房山大理岩三轴岩石力学试验测试数据进行了计算和分析,结果表明内聚力和内摩擦角随塑性体应变具有很好的相关性.因此,本文认为可以将塑性体应变作为塑性内变量进行大理岩弹塑性本构关系的研究.本项研究工作的开展对于其它种类岩石弹塑性本构关系的研究具有示范意义,能够为相关的工程建设和数值模拟工作提供基础数据.%Rock mechanical test is a main method to obtain rock material parameters,the plastic deformation and its affect to rock property could be acquired by a elastoplastic theory.Using the Mohr-Coulomb criteria,the cohesion strength and the friction angle could be calculated that corresponding to initial strength,peak strength and residual strength,and this is a great manner to learn rock elastoplatic property.Bathed on isotropic hardening or softening assumption,tri-axial rock mechanical test are performed which marble samples collected from Fangshan,Beijing.The analysis results show that the cohesion strength and the friction angle varied with the plastic body strain well.Thus the plastic body strain could be used as the internal variable to study this marble's constitutive relation.Method in this paper could be used in other rock material study; the results are useful for engineer designing and numerical modeling.