三峡引水工程秦巴段输水隧洞稳定性分析

三峡引水工程秦巴段隧洞总长占线路总长的80%。为了分析隧洞施工及运营中可能发生的工程地质问题,在地质调查、地应力测量和岩石力学参数测试的基础上,利用Ansys有限元软件对引水工程北部不同深度、不同截面形态的隧洞围岩的应力重分布情况进行了模拟计算,得到了圆形隧洞、城门形隧洞和马蹄形隧洞围岩的应力分布结果。利用Hoek-Brown强度准则,得到了隧洞围岩的强度/应力比值,进而对不同深度、不同截面形态的隧洞围岩的稳定性进行了分析。初步认为:隧洞埋深小于1000m时,应优先考虑圆形隧洞和马蹄形隧洞;埋深大于1000m时,应优先考虑城门形隧洞。这项研究成果为引水工程深埋隧洞的设计提供了参考依据。

Stability analysis of diversion tunnels in the Qinling-Dabashan, segment,center China of the Three Gorges Water Diversion Project

The total length of the Qinling-Daba segment of the Three Gorges Water Diversion Project accounts for 80% of the total length of the project line. In order to analyze the problems of engineering geology that may happen during tunnel construction and operations, geological surveys, ground stress measurements and rock mechanical tests were made, and on that basis, simulation calculation were performed of the stress redistribution of surrounding rocks of the tunnel with the circle- straight-wall-top-arch- and horse's hoof-shaped cross sections at different depths in the northern part of the water diversion project by using the Ansys finite element software. According to the Hoek-Brown strength criterion, the rock strength/stress ratio was obtained. Furthermore, the stability of the surrounding rocks of the tunnel with different cross sections at different depths was analyzed. It is preliminarily considered that in choice of the tunnel cross section in the design of the Three Gorges Water Diversion Project we should give priority to the circle- and hoof-shaped tunnels when the tunnel depth is <1000 m and to a tunnel with a straight-wall-top-arch section when the tunnel depth is >1000 m. This research achievement provides reference for the design of deep-buried tunnels of a water diversion project.