摘要
采用细观力学方法提出一个岩石各向异性损伤和渗流耦合的细观模型。其中,岩石的损伤由裂纹的状态变量来表示,损伤演化通过裂纹扩展准则来定义,并采用细观力学的分析方法由含裂纹材料的自由熵推导出裂隙岩石的本构方程。同时可以假设:由于裂纹表面的粗糙不平,在裂纹扩展的同时将引起法向开度的产生,这是材料渗透系数变化的主要原因,根据上述假设及达西定律和微观层流理论,推导出岩石特征体积单元的渗透系数表达式,从而建立岩石各向异性损伤和渗流耦合的细观模型。模拟分析表明,提出的模型与试验结果吻合很好。
A coupled model for anisotropic damage and permeability variation by using a micromechanical approach is presented.The damage state is represented by oriented distribution of microcracks,damage evolution in rock is defined from a crack propagation criterion;and the free entropy and constitutive law of cracked rock are obtained by using micromechanical method.It is assumed that the cracks exhibit normal aperture which is coupled with the crack growth due to asperities of crack faces.By using Darcy′s law for macroscopic fluid flow and assuming laminar flow in microcracks,the overall permeability of RVE is obtained by a volume averaging procedure taking into account crack aperture in each orientation.An analyzing case shows that the result by the model perfectly agrees with experimental one.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2007年第2期368-373,共6页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金委员会
二滩水电开发有限责任公司雅砻江水电开发联合研究基金项目(50579091)
中国科学院海外杰出学者基金资助项目(2004–1–7)
关键词
岩石力学
损伤
微裂纹
渗透系数
水–力耦合
脆性岩石
rock mechanics
damage
microcracks
permeability
hydromechanical coupling
brittle rocks
