不同应力环境中软弱夹层对洞室围岩稳定性影响研究

Influence of weak interbedding on stability and safety of underground in different confining pressure environment

不同应力环境中,软弱夹层表现出不同的力学行为,对地下洞室围岩稳定性与支护结构受力的影响差别明显,本文利用奥地利大型岩土工程分析系统FINAL,系统分析不同类别代表性围岩、不同侧压力条件下软弱夹层对隧洞围岩位移场、应力场、塑性区分布以及喷层受力的影响。由于夹层分布在边墙部位时影响最为明显,本文着重研究夹层分布在边墙部位的情况。通过大量的有限元分析,系统地讨论不同侧压力系数下夹层对隧洞围岩位移场、应力场、塑性区分布与喷层变形与应力的影响,总结洞室关键点位移、围岩应力、围岩塑性区以及喷层应力随侧压力系数的变化关系,得到软弱夹层对围岩位移、支护结构内力一些无量纲的量化指标,提出不同应力条件下软弱夹层对围岩稳定性、支护结构安全性影响的一般规律。

Weak interbedding plays an important role in the stability of srurrounding rock, and presents different influence in stress field with various confining coefficient. Systematic numerical tests have been carried out to study the stability of surrounding rock mass with a weak interbedding distributed in wall side under the condition of initial stress with 5 different eonfining coefficients（0.38, 1.0, 1.5,2.0,3.0） respectively, the safety status of the supporting system has been also analyzed by the FEM program FINAL introduced from Austria. A perfect element to simulate the weak interbedding has been used in all test models. Some quantification results are summarized into influence of weak interbedding, especially the displacements, stresses, plastic region in surrounding rock and stress in shotcrete. The results will be devoted to layout, supporting system design and construction of underground tunnel.