采空区对铁路隧道工程结构影响分析

Effect of Abandoned Mining Caverns on the Railway Tunnel Structures

随着我国高速铁路建设的发展,越来越多的新建铁路工程位于矿产地下采空区附近,矿区开采后形成的采空区对铁路隧道工程安全性影响已日益成为亟需解决的工程问题。针对采空区引起地表塌陷危及隧道安全的问题,结合张吉怀铁路隧道工程情况,通过理论分析类比法,并采用Flac3D有限元软件进行数值计算,综合分析了杜夜锰矿地下采空区引起的地面变形影响范围以及铁路隧道变形情况。结果表明,杜夜锰矿开采后的采空区引起的围岩变形主要集中在矿体上方以矿体底部按岩石移动角作斜线包含的区域,区域外围岩变形迅速变小;采空后引起张吉怀铁路隧道变形影响距离保守估算取221m;杜夜锰矿采空区引起的隧道变形在允许范围内。

With the development of China’s high-speed railway construction,more and more high-speed railway projects are aligned over areas with unfavorable geological conditions,such as,abandoned mining caverns.The stability of the railroad over mining caverns becomes increasingly more important and need to be addressed.This paper presents a case history of the ground subsidence and cavern collapse evaluation for a railway tunnel near the abandoned mining caverns in Zhang Jihuai High-speed Railway Project.Based on the analogy analysis,the ground subsidence area of an abandoned Du Ye manganese ore mining caverns and its influence zone as well as the tunnel deformation are numerically simulated by the FLAC 3 Dfinite element software.The results indicate that,the deformations of the abandoned mining caverns were concentrated in the upper crown area and area along the bedrock dip direction;areas outside the deformation concentration has little deflections.The influence distance for the abandoned mining cavern on the railway tunnel is conservatively taken as 221 meters and the deformation of the tunnel induced by the mining caverns are within the allowable limits.