卵砾层中大跨浅埋隧道开挖变形监测与反分析

Monitoring Deformation Behavior of Shallow Buried Large-span Tunnel in Gravel Deposits During Excavation and Its Analysis

国内外在岩土介质环境中修建隧道与地下工程积累了相对多的设计与施工经验,而对卵砾石层这种特殊粗细料混合介质,研究相对较少。以某高速公路特殊卵砾石层中大跨浅埋公路隧道为例,通过分析围岩变形监测资料,探讨卵砾石层中大跨公路隧道围岩及结构在隧道开挖过程中的变形行为,并对卵砾石层的弹性模量进行了反演,得到了更符合实际情况的计算参数。研究成果可以用来指导现场施工和优化支护设计,并对以后该种特殊地质条件下类似工程的规划设计及施工提供参考。

The experiences and techniques of tunnel construction are mostly accumulated from rock and soil tun- nel construction.However,relative rare experiences have been reported on special gravel tunneling.A ease study of one mountain highway tunnel is carried out in this paper,which has the characteristics of large span and shallow over- burden.Systematic monitoring on the displacements of the ground surface and the surrounding rock is undertaken for evaluating the deformation behavior of gravel tunnel during excavation.Moreover,with the measurement data,dis- placement-based back analysis is introduced to get the Young's modulus of gravel deposits.The findings are useful for the optimum design and construction control for this project or other projects with similar conditions.