岩石化学腐蚀-围压细观损伤本构模型与离散元模拟研究

基于Lemaitre应变等价性假设理论，假定受水化学-力耦合损伤的岩石微元强度服从Weibull分布，考虑化学腐蚀与围压耦合作用对岩石力学参数的影响，通过核磁共振技术与损伤力学理论，引入细观化学损伤变量与力损伤变量，并认为微元破坏符合SMP准则，建立岩石化学腐蚀-力耦合损伤本构模型，并采用理论推导的方法得出所需的模型参数。同时基于颗粒离散元方法，引入参数半径乘子来改变颗粒间的黏结接触尺寸，从而模拟水化学损伤，采用平直节理模型对水化学作用后的岩石进行三轴压缩模拟，得到了水化学作用和不同围压下的岩石三轴应力-应变模拟曲线。通过对比所构建的岩石化学腐蚀-力耦合损伤本构模型理论曲线、离散元模拟曲线和试验曲线，结果表明三者吻合度较好，能够很好地反映岩石在化学腐蚀和围压耦合作用下的力学特性与破坏特征，并通过离散元方法得到了岩石在三轴压缩过程中裂纹的产生与分布情况。

Chemical Corrosion-Confining Pressure Meso-Damage Constitutive Model and Discrete Element Simulation of Rock

Based on Lemaitre's theory of strain equivalence hypothesis, and the influence of chemical corrosion and confining pressure coupling on rock mechanical parameters is considered. Through nuclear magnetic resonance technology and damage mechanics theory, The meso-chemical damage variables and force damage variables are introduced, and the micro-element damage conforms to the SMP criterion, the evolution equation and constitutive model of the rock chemical corrosion-mechanics coupling damage are established, and the required model parameters are obtained by the method of theoretical derivation. Based on the particle discrete element method, the parameter radius multiplier was introduced to change the size of the bonding contact between particles, so as to simulate the hydrochemical damage. The flat joint model was used to simulate the triaxial compression of the rock after hydrochemical action, and the triaxial simulation curves of the rock under hydrochemical action and different confining pressures were obtained. By comparing the theoretical curve, discrete element simulation curve and test curve of the constructed rock chemical corrosion-mechanical coupling damage constitutive model,the results show that the three curves are in good agreement and the generation and distribution of cracks in rock during triaxial compression are obtained by discrete element method.