考虑时效损伤劣化的变参数非线性蠕变损伤模型

应力长期作用下岩体内部损伤不断累积、扩展，导致部分承载单元丧失承载能力，使得岩体内部真实应力强度大于表观应力。该文以流变学理论为基础，将损伤因子引入弹性元件及黏性元件中，给出弹性损伤元件及黏性损伤元件的蠕变特征方程，用以描述持荷过程中由于损伤累积而呈现出蠕变与时间相关的非线性变形特征；然后以弹性损伤元件及黏性损伤元件的蠕变特征方程为基础，给出考虑损伤效应的经典组合模型的蠕变状态方程，并依据稳定蠕变过程中蠕变变形的组成特征，构建了用于描述软岩稳定蠕变的五元件变参数非线性蠕变损伤模型，同时给出了蠕变损伤组合模型的蠕变变形特征方程；最后以江西东乡铜矿砂质页岩稳定蠕变阶段实验数据为基础，分析并验证了蠕变损伤模型在描述软岩非线性蠕变特征方面的准确性及适用性，拟合结果表明:引入损伤因子的蠕变模型元件，能够很好的描述蠕变的时效-非线性特征。

VARIABLE PARAMETERS NONLINEAR CREEP DAMAGE MODEL OF ROCK WITH CONSIDERATION OF AGING,DAMAGE AND DETERIORATION

The loss in bearing capability of partial bearing elements, which are subjected to the loads in the long-term, will be induced by the accumulation and development of internal damage. Because of the above phenomenon, the actual stress strength in internal parts of rocks is usually higher than the apparent stress strength. Based on rheology theory, the damage factor is introduced into the elastic and viscous elements. The creep equations of elastic-damage and viscous-damage element, which are used to depict the time-depending nonlinear characteristics of creep caused by damage accumulation in the process with constant loading, is proposed. Then, based on the characteristic creep equations of elastic-damage and viscous-damage elements, the creep equation of state of the classical combined model, where damage effects have been considered, is proposed. According to component characteristics of creep in the steady creep state, the nonlinear creep-damage model, which is characterized by five-element parameters, has been established and used to depict the steady creep of soft rock. At the same time, the characteristic equation of the combined model, which is characterized by creep damage, has also been established. Finally, based on the experimental data in steady creep stage conducted on the sandy shale from the Dongxiang copper mine in Jiangxi, analysis of the accuracy and feasibility of the combined model, which is used to depict the nonlinear creep characteristics of soft rocks, is conducted. The results of curve-fitting show that the aging-nonlinear characteristics can be depicted satisfactorily by introducing the damage factor into the creep elements.