考虑孔隙压密的岩石非线性变形行为计算分析  

Numerical analysis on nonlinear deformation behavior of rock considering compaction of pores

作　　者：王青元 朱万成[2] 徐涛[2] 刘洪磊[2] 贾建功 WANG QingYuan;ZHU WanCheng;XU Tao;LIU HongLei;JIA JianGong(Department of Resources and Environment, Heze University, Heze 274015, China;Center for Rock Instability and Seismieity Research, Northeastern University, Shenyang 110819, China;Heze Coal Administration Bureau, Heze 274015, China)

机构地区：[1]菏泽学院资源与环境系,菏泽274015 [2]东北大学岩石破裂与失稳研究中心,沈阳110819 [3]菏泽市煤炭管理局,菏泽274015

出　　处：《中国科学：技术科学》2018年第5期565-574,共10页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:51374049;51474051);菏泽学院博士基金(编号:XY16BS36)资助项目

摘　　要：含孔隙裂隙岩石的非线性变形对分析岩体工程中的力学响应和安全评价具有重要意义.需要考虑岩石的孔隙性建立能够反映岩石变形非线性特性的本构模型.本文首先分析了岩石非线性变形的力学机理,将岩石的全应力应变曲线分成两段.然后对两段分别建立本构关系:在压密闭合阶段,提出压密因子的概念,以表征孔隙率变化对岩石变形特性的影响;除压密闭合阶段外的另一阶段,基于损伤理论,采用岩石细观单元本构模型来描述,以最大拉应变准则和摩尔-库仑准则作为损伤判断准则.借助有限元分析软件COMSOL Multiphysics,通过MATLAB编程实现对该模型的数值求解.为验证模型的正确性,将数值模拟得到的结果与试验数据进行对比.最后,对6种孔隙率不同但岩石基质相同的岩石进行了单轴压缩破坏过程数值模拟.研究结果表明:运用提出的压密因子所建立的本构模型可以很好地模拟岩石的压密闭合阶段的非线性,对同种岩石孔隙率越大单轴抗压强度越小,随孔隙被压密弹性模量越来越大.The nonlinear behavior of porous or fractured rocks plays an important role for analyzing the mechanical response and stability in many geological and geotechnical applications. A stress-strain relationship considering the porosity is established for modeling the nonlinear deformation. In the present paper, firstly, on the basis of nonlinear deformation mechanism of porous or fractured rocks, the typical stress-strain curve was divided into two parts factitiously. Then, two constitutive models were established for the two parts,respectively. In order to describe the effect of the change of porosity on deformation behavior of rock, a new microcracks closure factors D？was proposed in the microcracks closure phase. For the other part, elastic damage mechanics is used to describe the constitutive law of meso-level elements, the maximum tensile strain criterion as well as the Mohr-Coulomb criterion is utilized as the damage threshold. The proposed model is implemented using finite element method by MATLAB programming under the environment of COMSOL Multiphysics. Then the model was validated by comparing the numerical simulations with our experimental result and the previously published experimental data. At last, numerical simulation on failure process of 6 rock specimens with different porosities but same rock matrix under uniaxial compression is presented. It is found that the established model accurately reproduces the typical stress-strain curve, the microcracks closure phase, especially. With the increase of porosity,the uniaxial compressive strength（UCS） decreases. And the elasticity modulus increases with the porosity decrease.

关 键 词：孔隙率 应力应变关系 非线性 压密因子 数值模拟 

分 类 号：TU45[建筑科学—岩土工程]