基于改进RMR方法的深部隧道稳定性分析

Analysis on Stability of Deep Tunnel Based on Modified RMR Method

为了解决在岩石工程领域中的基于地质力学的岩体评级方法只适用于浅部岩层,而在大埋深、高应力环境中出现不适应性这一问题而展开研究,首先,从RMR分类方法入手,通过引入能较好反映岩体质量的岩体块度指数,并考虑地应力的影响,对传统的RMR分类方法进行改进,以确定出改进后的评估值RMRnew;其次,基于RMRnew确定出隧道支护体系的作用荷载,并对支护体系进行分析,确定其极限承载能力;最后,基于荷载-结构法构建起隧道稳定性分析框架,并对隧道安全状态进行评估。对工程实例进行分析发现,基于改进后的RMR分类方法所得到的分析结果与实际情况相符,说明地应力、岩块尺寸以及埋深等对隧道稳定性有明显影响。

The method of rock mass rating （RMR） based on geological mechanics in the field of rock engineering applies only to shallow strata but does not adapted to large bused depth and high stress environment. In order to solve this problem, First of all, based on the RMR classification method, by introducing rock block index which can better reflect rock quality into the method, and considering the influence of in-situ stress, the traditional RMR rock mass classification system is improved to determine RMR the modified value. Then, the load on tunnel support system is detern^ined based on the RMR and the support system is analysed to determine its ultimate bearing capacity. At last, the analysis framework of tunnel stability is constructed based on load-structure method, and the tunnel safety status is analysed. The analysis of a project example shows that the analysis result based on the modified RMR method is consistent with the actual situation, which illustrates that in-situ stress, rock block size and buried depth have obvious influence on the stability of tunnel.