青藏铁路昆仑山隧道稳定性分析

Stability Analysis of Kunlun Mountain Tunnel for Qinghai-Tibet Railway

在地质构造分析、地应力测量、地应力场的反演和岩石力学实验的基础上 ,对昆仑山隧道多种断面的应力分布进行了有限元计算 ,给出不同断面的应力分布图象 ,指出了不同断面应力分布的特点以及断面形状对应力分布的影响 ,同时计算了围岩的强度与应力比 ,对围岩稳定性进行了分析对比 。

The Qinghai Tibet Railway is a great engineering project and also constitutes a major part in the development of western China, thus becoming one of the focuses of world attention. Construction of the railway is of great significance. The railway is planned to pass through an average height of 4 500～5 000 m above sea level and has a total length of 1 110 km, with several tunnels more than 11 km in total length to be excavated. One of them is the Kunlun Mountain tunnel over 1 600 m long surrounded by rocks of low quality. A study of the tunnel stability is very important to safety. On the basis of geological structural analysis, rock stress measurement, rock mechanical experimentation and inversion of tectonic stress field, this paper calculated stress distribution of tunnels in different sections by using finite element method. Stress pattern and ratio of rock strength to stress are given. Optimization of sections is made. It is shown that a tunnel which has curve sides and an arch bottom with ratio 1.08 of width to height is more stable than other types. Scientific basis is provided for reasonable designing, construction and long term stability of the tunnel.