基于压缩载荷下微裂纹扩展的微观力学岩石弹塑性损伤模型研究  

Elastoplastic damage model of rock based on micro-crack propagation under compression

作　　者：袁小平[1] 李波涛[2] 刘红岩[1] 王志乔[1] 孙鸣雷[1] 

机构地区：[1]中国地质大学(北京)工程技术学院,北京100083 [2]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《中南大学学报（自然科学版）》2012年第8期3200-3208,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41002113;41162009);中央高校基本科研业务费专项资金资助项目(2011PY0190;2010ZY45);教育部科学技术研究重点项目(2011175)

摘　　要：建立基于微裂纹扩展的岩石弹塑性损伤微观力学模型。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弹塑性损伤模型的程序。分析弹塑性损伤模型的基本特性和围压对岩石损伤的影响,并从围压和短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2个单轴压缩岩石试验为例验证该模型。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 was presented. The propagation of wing crack in the micro-crack tip was characterized for rock damage, and the wing crack length was obtained using Newton iteration based on the strain energy density for mixed-mode fracture. The distribution of micro-cracks was presented by the absolute volume strain with the two-parameter Weibull statistical model. The damage evolution variable of rock was employed by the distribution of micro-cracks and stress release volume was described by lengthen of wing-crack. Voyiadjis＇s strain hardening function was employed as the plastic yield function and plastic potential function. The elastoplastic damage model with its numerical algorithm was proposed and the code of elastoplastic damage model was implemented by using return mapping implicit integration algorithm. The influences of rock confining pressures on the damage response in the elastoplastic damage model were analyzed, The plastic properties of the rock were also analyzed from the aspects of short micro-crack lengths, confining pressures. The results show that the proposed elastoplastic damage model agrees well with the experimental results for two rock tests under uniaxial compression .

关 键 词：微裂隙 应变能密度 NEWTON迭代法 塑性 损伤演化 隐式积分算法 

分 类 号：O342.1[理学—固体力学]