摘要
在变形体离散元的框架内引入界面单元,提出模拟岩石等准脆性材料破坏过程的连续-离散耦合分析方法。假定损伤和断裂只发生在界面单元上,实体单元只产生弹性变形,采用带拉断的Mohr-Coulomb准则和标量损伤因子来模拟界面单元的损伤、失效过程,实现岩石由连续性向非连续性转换的物理过程。在数值试验中,岩石细观尺度上单元的弹性模量和单轴抗压强度服从Weibull概率分布并满足一定的相关性。数值模拟结果表明:本文方法能反映岩石在加载过程中的线弹性、非线性、软化、残余4个阶段和主要特点;能显式地模拟微裂缝的萌生、扩展直至贯通形成宏观裂缝的全过程;反映岩石强度的围压依赖性和脆-延-塑转换力学特性。
In the framework of deformation discrete element method, a continuous-discontinues coupling for simulating failure process of quasi-brittle materials such as rock is proposed by introducing interface element. It is assumed that damage and fracture occur only in interface element, while solid element has elastic deformation. Mohr-Coulomb criterion with tension cut-off is used as damage initiation criterion; a scalar damage variable representing overall damage in the material is used to describe the rate at which the material stiffness is degraded; crack is simulated explicitly by failure of interface element. Continuous-discontinuous transition process of rock can be realized. In the numerical experiments, mechanical parameters of solid element are randomly allocated according to Weibull distribution and have certain correlation. The numerical simulation results show that the suggested method can reflect the linear elasticity, nonlinearity, softening and residual phases during the loading process of rock; it can explicitly simulate the crack propagation. The simulation results also show that rock has confining pressure effect and brittle-ductile-plastic transition.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2011年第12期2444-2455,共12页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学杰出青年基金项目(50725931)
国家自然科学基金重点项目(50839004)
国家自然科学基金资助项目(50979082)
关键词
岩石力学
变形体离散元
界面单元
数值试验
非均匀性
脆-延-塑转换
rock mechanics
deformable discrete element
interface element
numerical experiment
heterogeneity
brittle-ductile-plastic transition
