考虑微裂纹相互作用的岩石细观力学弹塑性损伤模型研究  

AN INTERACTING CRACK-MECHANICS BASED MODEL FOR ELASTOPLASTIC DAMAGE MODEL OF BRITTLE MATERIALS UNDER COMPRESSION

作　　者：袁小平[1] 刘红岩[1] 王志乔[1] 

机构地区：[1]中国地质大学(北京)工程技术学院,北京100083

出　　处：《固体力学学报》2012年第6期592-602,共11页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金(10902111);中央高校基本科研业务费专项资金(2010ZY33和2012069)资助

摘　　要：论文建立基于微裂纹扩展的岩石弹塑性损伤细观力学模型.用自洽方法考虑裂隙间相互影响,压缩载荷下微裂纹尖端翼裂纹稳定扩展表征岩石的微观损伤,基于应变能密度准则用Newton迭代法求复合型断裂的翼裂纹扩展长度,并采用微裂隙统计的二参数Weibull函数模型反映绝对体积应变对微裂纹分布数目影响,进而用翼裂纹扩展所表征的应力释放体积和微裂纹数目来表示含有微裂隙的岩石损伤演化变量;宏观塑性屈服函数采用Voyiadjis等的等效塑性应变的硬化函数,反映塑性内变量对硬化函数的影响;建立岩石的弹塑性损伤本构关系及其数值算法,并用回映隐式积分算法编制了弹塑性损伤模型的程序.从围压和微裂隙长度等因素分析弹塑性损伤模型的岩石的损伤和宏观塑性特性.以1个单轴压缩岩石试验为例,结果表明所提出的弹塑性损伤模型与数值和试验结果比较吻合.A micro-crack elastoplastic damage model under compressive loading is presented in this work. Interactions among the cracks are modeled by self-consistent approach in which each crack experi- ences a stress field different from that acting on isolated cracks. The propagation of wing crack in the mi- cro-crack tip is characterized for rock damage, and the wing crack length is obtained using Newton iteration based on the strain energy density for mixed-mode fracture. The distribution of micro-cracks is presented by the absolute volume strain with the two-parameter Weibull statistical model. The damage evolution vari- able of rock is employed by the distribution of micro-cracks and stress release volume described by length of wing-crack. Voyiadjis′s strain hardening function is employed as the plastic yield function and plastic po- tential function. The elastoplastic damage model with its numerical algorithm is proposed and the code of e- lastoplastic damage model is implemented by using return mapping implicit integration algorithm. The in- fluence of rock confining pressures on the damage response in the elastoplastic damage model is analyzed. The results show that the proposed elastoplastic damage model agrees well with the experimental results for one rock test under uniaxial compression.

关 键 词：应变能密度 NEWTON迭代法 微裂纹相互作用 损伤演化 隐式积分算法 

分 类 号：TU45[建筑科学—岩土工程]