秦岭终南山高应力公路隧道及洞群稳定性分析

Stability Analysis of Highway Tunnel and Tunnels Group in Qinling Zhongnan Mountain under a High Stress Environment

秦岭终南山公路隧道是目前世界第二长的公路隧道,其建设规模居世界第一。高应力,强岩爆倾向和复杂洞群结构是影响隧道2#竖井工程稳定性的主要因素,因此,对其施工过程的洞群围岩及空间结构力学演化特征进行研究,将为隧道及洞群优化设计提供科学的定量化依据和施工安全保障体系。本文利用岩石力学综合测试和数值模拟手段对隧道及洞群结构受力特征进行了分析,结果表明,混合片麻岩在高应力作用下具有瞬间发生脆性破坏的特点,洞群围岩在高应力区域具有岩爆倾向;同时,洞群开挖后空间力学特征复杂,施工时相互影响作用明显,特别是四连拱段拱脚高应力集中区域以及风道跨越主隧道段洞群之间低应力结构等将对整个洞群稳定性造成影响,为整个竖井工程施工中的关键部位。

This paper is centering on the highway tunnel project of Qinling Zhongnan Mountain,which is the first in construction scale and the second in length all over the world.High stress,tendency to strong rock burst and complex structure of tunnels group,is the dominant factor that influenced the stability of the 2# shaft project.During the analysis,rock mechanical test and numerical simulation were used.According to the result,on the one hand,it indicated that the migmatitic gneiss has brittle failure feature under the high stress conditions,and the rock burst may occur in the high stress region of the tunnels group; On the other hand,the caving of tunnels group induced a complex mechanical state near tunnels,and the interaction was obvious,especially to the high stress concentration areas of the four continuous arches skewbacks and the low stress structure between the main tunnel and tunnels group,which are the key parts and will affect the intact stability of the project.Therefore,to study the mechanical variation features of the surrounding rock and spatial structure is important for providing a scientific design to the tunnel and tunnels group,and forming a system of construction safety guard.