我国铁路隧道通用图结构安全性的计算研究

我国既有铁路隧道大多按标准图或通用图设计,而标准图或通用图又是采用工程类比法设计,因此不能给出明确的结构安全系数。为了给今后的铁路隧道设计优化与既有隧道维护提供技术支撑,采用所建立的复合式衬砌总安全系数设计法,对以往标准图或通用参考图的结构安全系数进行校核,对影响安全性的主要因素进行分析,得出以下主要结论:(1) 2008年以来编制的铁路隧道通用参考图,结构总安全系数均偏高,具有一定的优化空间;而20世纪编制的时速140 km单线电气化铁路隧道标准图在软弱围岩地段的总安全系数偏低;(2)隧道埋深对安全系数的影响较大,地下水发育程度对耐久性影响较大,建议按照不同埋深、不同地下水发育程度进行支护参数优化;(3)隧道断面形状对安全系数影响较大,建议根据围岩压力分布形态采取合理的断面形状。

Calculation and Study on the Structure Safety of Railway Tunnel Standard Drawings of China

The existing railway tunnels in China are mostly designed based on standard or general drawings,and these standard or general drawings are designed with engineering analogy method,which,as a result,fails to give definite structural safety factor. In order to provide technical support for tunnel design optimization and existing tunnel maintenance,the general safety factor design method of composite lining is used to check the safety factors of the previous standard drawings or general reference diagrams of China,and the main factors affecting the safety are analyzed. The research conclusions are as follows:(1) The general safety factors of railway tunnel standard drawings compiled in China after 2008 are higher and have certain optimization space; while the total safety factors of 140 km/h single track electrified railway tunnels standard drawings compiled in 20 th century are relatively low in weak surrounding rock area;( 2) The depth of the tunnel has great influence on the safety factor,and the degree of groundwater development has a great impact on the durability. It is suggested that the corresponding support parameters should be adopted according to the different depth and the development degree of groundwater;( 3) The tunnel sectional form has great influence on safety factor. Therefore,reasonable sectional form should be taken according to the surrounding rock pressure distribution pattern.