GSI围岩评级系统下围岩新型统计损伤模型

A New Statistical Damage Model of Surrounding Rock under GSI Surrounding Rock Rating System

为了得到受采动干扰、具有一定结构面的巷道围岩的变形破坏机理,采用GSI围岩评级系统对Hoek-Brown准则进行修正来描述岩石微元的强度,通过组成岩石力学性能参数变量的随机性与复杂性,假设岩石材料的力学性能满足对数分布,结合统计损伤力学理论和有效应力原理,建立不同围压作用下的岩石新型统计损伤模型,对岩石的损伤演化规律和应力应变关系进行研究。结果表明:通过GSI围岩评级系统改进后的破坏准则与试验数据有更好的一致性、更加符合实际;不同种类岩石在不同围压作用下的模型曲线与试验数据拟合程度较高,也说明该本构模型的合理性与正确性;不同围压作用下岩石的损伤演化规律基本呈现S形变化,可以与围岩应力应变曲线各阶段的破坏变形进行较好地对应与划分,且描述岩石的损伤演化规律与实际围岩的破坏过程基本一致,对实际工程具有指导意义。

In order to obtain the mechanism of deformation and failure of roadway surrounding rock that was disturbed by mining with a certain structural surface,the GSI surrounding rock rating system was adapted to the Hoek-Brown criterion to describe the strength of rock microelements. By composing the randomness and complexity of the rock mechanical performance parameter variables,it was assumed that the mechanical properties of rock materials satisfy the logarithmic distribution. The theory of statistical damage mechanics and the principle of effective stress were combined to establish a new type of statistical damage model for rocks under different confining pressures. The damage evolution law and stress-strain relationship of the studied rock were studied. The results show that the damage criterion improved through the GSI surrounding rock rating system is better consistent with the test data and more consistent with the actual test data. The model curves of different kinds of rocks under different confining pressures were quite fitted to the experimental data. It also shows that the constitutive model is reasonable and correct. The damage evolution of rocks under different confining pressures basically showed S-shaped changes. It could basically correspond and divide well with the deformation and deformation of the surrounding rock stress-strain curve at each stage. The description of the damage evolution law of rock was basically the same as that of the actual surrounding rock. It had guiding significance for practical engineering.