基于渗流-损伤-应力耦合作用下考虑力学参数弱化的巷道围岩变形破坏分析

DEFORMATION AND FAILURE OF SURROUNDING ROCK CONSIDERING WEAKENING OF MECHANICAL PARAMETERS UNDER SEEPAGEDAMAGE-STRESS COUPLING

地下工程岩体渗流-损伤-应力耦合问题的研究对于巷道围岩的稳定性分析具有重要意义。本文在总结分析了巷道变形破坏类型影响因素的基础上,基于弹塑性力学、渗流力学以及损伤理论建立了岩体渗流-损伤-应力耦合模型。该模型充分考虑了多物理场耦合过程中,工程岩体的非均质性,岩体力学参数发生的动态弱化过程,围岩塑性屈服的峰后特性以及渗透系数在损伤过程中的突变性。基于多物理场耦合软件,数值模拟结果分析得到,使用该模型能更好地反映巷道围岩的屈服破坏程度和渐进破坏过程。应用该模型分析不同深度下的巷道围岩渐进性破坏过程可以得出:水平地应力为主导的地层中的巷道,屈服破坏主要发生在顶拱和底板,竖直地应力为主导的地层中的巷道,屈服破坏主要发生在两侧边墙,水平地应力和竖直地应力相近的地层中,巷道四周均发生不同程度的破坏,这与工程实际有很好的符合。

The study on seepage-damage-stress coupling of underground engineering rock mass is of great significance for the stability analysis of surrounding rock. This paper presents an improved model of seepage-damage-stress coupling based on elastic-plastic mechanics, seepage mechanics and damage theory. In this model, we fully consider the heterogeneity of rock mass, the dynamic weakening process of rock mass mechanical parameters, the post-peak characteristics of plastic yield of surrounding rock and the abrupt change of permeability coefficient in the process of damage. This model can better reflect the yield damage and progressive failure process of the surrounding rock, which is obtained from the analysis of numerical simulation results with the multi-physics coupling simulation software. In order to verify its validity, this model is used in the analysis of the progressive failure process of surrounding rock at different depths. The result is in good agreement with the results from the engineering practice.