压缩载荷作用下岩石的细观损伤和塑性研究

建立岩石微裂纹扩展的细观力学模型,研究了岩石的细观损伤和塑性性质.压缩载荷下微裂纹尖端翼裂纹稳定扩展表征岩石的细观损伤,采用应变能密度准则求解复合型断裂的翼裂纹扩展长度,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,反映了塑性内变量对硬化函数的影响;建立岩石模型的本构关系及其数值算法,并用回映隐式积分算法编制了模型的本构程序.分析弹塑性损伤模型的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模型的岩石的损伤和宏观塑性特性.

Crack-mechanics damage and plasticity for rock-like materials under compressive loading

A crack-mechanics based model of rock together with plasticity under compressive loading is presented in this work.The propagation of wing crack in the micro-crack tip is characterized for rock damage,and the wing crack length is obtained 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 variable of rock is employed by the distribution of micro-cracks and stress release volume.Voyiadjis's strain hardening function is employed as the plastic yield function and plastic potential function.The elastoplastic damage model with its numerical algorithm is proposed and the code of elastoplastic damage model is implemented by using return mapping method.The plastic properties of the rock are analyzed from the respects of short micro-crack lengths,confining pressures.