基于应变能的岩石黏弹塑性损伤耦合蠕变本构模型及应用

在Perzyna黏弹塑性理论的基础上，引入基于应变能理论的岩石细观单元强度损伤模型，同时考虑岩石蠕变过程中蠕变速率随时间变化的特性，构建了能描述岩石从初始蠕变、稳定蠕变到非线性加速蠕变整个蠕变过程的细观黏弹塑性损伤耦合蠕变本构模型，并将该模型嵌入到三维弹塑性细胞自动机模拟系统(EPCA3D)中，通过实验数据验证该模型的正确性。应用该模型进行不同轴向应力、不同围压和不同均质度系数条件下的单、三轴压缩蠕变过程数值实验，结果表明:① 轴向应力提高增加了蠕变速率，因此减少了蠕变失效时间;② 围压和均质度系数的增加降低了蠕变速率并增加了蠕变失效时间，较好的再现了典型的实验现象。将该模型用于解释煤矿中“蠕变型”冲击地压的力学机理，较好的反映了煤矿巷道开挖后弹性应变能累积，围岩经历稳定蠕变和加速蠕变的损伤破坏过程，可为岩体工程的长期稳定性研究提供分析工具。

A coupled elasto viscoplastic damage model based on strain energy theory of rock and application

On the basis of elasto viscoplastic theory of Perzyna,a mesoscopic coupled elasto viscoplastic damage model,describing the whole creep process of rock from initial creep,stable creep to nonlinear acceleration creep,is constructed by introducing a mesoscopic unit strength damage model based on the strain energy theory.The characteristics of the creep rate change with time in the creep process of rock can be taken into consideration,and can be integrated into the EPCA3D.The model was verified by the experimental data and then applied to the numerical experiments of single and triaxial compression creep process under different axial stresses,confining the pressures and homogeneity coefficients.The results showed that,on one hand,the increased axial stress can speed up the creep rate,which reduces the creep failure time.On the other hand,the increased confining pressure and homogeneity coefficient can reduce the creep rate and lead to the increase of creep failure time.This study can better reproduce the typical experimental phenomena.It can be used to explain the mechanical mechanism of creep induced rock burst in coal mines,and also better reflect the accumulation of elastic strain energy after the excavation of coal mine roadway and the damage process of surrounding rock undergoing stable creep and accelerating creep.This study can provide an analytical tool for the long term stability of rock mass engineering.