考虑初始损伤和蠕变损伤的岩石蠕变全过程本构模型  

A creep constitutive model of rock considering initial damage and creep damage

作　　者：王其虎 叶义成[1,2] 刘艳章[1,2] 姚囝 

机构地区：[1]湖北省页岩钒资源高效清洁利用工程技术研究中心,湖北武汉430081 [2]武汉科技大学资源与环境工程学院,湖北武汉430081

出　　处：《岩土力学》2016年第S1期57-62,共6页Rock and Soil Mechanics

基　　金："十二五"国家科技支撑计划课题(No.2011BAB05B03);国家自然科学基金(No.51074115);湖北省科技支撑计划(No.2014BCB033)~~

摘　　要：考虑到天然岩石存在不同程度初始损伤以及蠕变过程中岩石受载后裂隙扩展而导致的新损伤,对具有初始损伤的岩石蠕变特性进行全面描述。根据不闭合结构面应力与法向变形之间的关系,提出裂隙岩石塑性变形体元件,描述岩石蠕变过程中的瞬时塑性变形。引入初始损伤影响因子,建立具有初始损伤的岩石损伤变量演化方程,构建模拟岩石加速蠕变的蠕变损伤体元件。将裂隙岩石塑性变形体和蠕变损伤体与描述瞬时弹性变形和黏弹性变形的广义开尔文模型进行串联组合,形成能够反映具有初始损伤的岩石瞬时弹-塑性变形、稳定蠕变和加速蠕变的蠕变全过程本构模型,提出了进行少量蠕变试验既能解析模型参数的方法,在不同应力水平下模型理论曲线与蠕变试验曲线吻合。Natural rock contained a large number of microcracks generated and accumulated in the long-term geological activity. In early loading stages or under a low stress level, rock would experience a fracture compression phase, in which rock showed out nonlinear instantaneous plastic deformation. Without considering rock instantaneous plastic deformation by fracture compression, the normal rock creep model reflected lower instantaneous deformation value than the real. Therefore, it is necessary to consider effect of initial damage on rock creep in process of constructing rock creep constitutive model. Considering different degrees of initial damage existing in the natural rock and new damage caused by crack extension under loading in the process of rock creep, the creep properties of rock with initial damage in different stress levels is overall described. With the increase of stress, rock creep would experience steady creep with instantaneous elastic deformation, steady creep with instantaneous elastoplastic deformation and accelerated creep. Based on the relationship between stress and normal deformation of the unclosed structural plane, concluded by BANDIS S C and BARTON N R through many tests, a mechanical component of fracture rock plastic deformation body is put forward to describe instantaneous plastic deformation in rock creep process. Considering the initial damage having effect on accelerated creep, an initial damage factor is introduced to Kachanov creep damage variable evolution equation, a damage variable evolution equation of the rock with initial damage is built. Furthermore, a creep damage body component is put forward to simulate accelerated creep of rock. The fracture rock plastic deformation body component and the creep damage body component are series connected to the generalized Kelvin model which can describe instantaneous elastic deformation and viscoelastic deformation of rock, to form a whole creep process constitutive model which could reflect instantaneous elastoplastic deformation, steady cr

关 键 词：岩石蠕变 初始损伤 瞬时塑性变形 蠕变损伤 加速蠕变 本构模型 

分 类 号：TU45[建筑科学—岩土工程]