冰水堆积体隧道施工过程变形与受力分析

为探明冰水堆积体公路隧道施工期间围岩变形和支护体系特性,以在建国道317线雀儿山隧道为工程依托,通过现场实验对冰水堆积体围岩物理力学参数及施工特性进行分析,采用现场测试方法对施工过程中隧道地表下沉和洞周变形,锚杆轴力、钢拱架内力、围岩-初期支护接触压力等支护体系特性进行研究。结果表明:(1)冰水堆积体围岩隧道粒度粗细悬殊且粗细混杂岩性变化大,垂直方向上主要分为冰水积含碎石砂卵砾石层和冰漂砾块碎石层;(2)水平方向上围岩构成和分布是影响锚杆轴力、拱架内力、围岩与初支的接触压力变化及分布的主要影响因素;(3)采用三台阶预留核心土法施工安全可控。

Analysis of Deformation and Stress during Outwash Accumulation Tunnel Construction

In order to identify the deformation of surrounding rock and the behavior of supporting system during outwash accumulation tunnel construction, experimental tests and engineering characteristic analysis of physical and mechanical parameters and field tests are conducted to examine the variation laws of the surface subsidence and deformation around the tunnel with outwash accumulation,the axis forces of anchors,the contact pressure between the wall rock and primary bracing,and the internal forces in arch frames during construction period with reference to the under-construction Que'er Shan tunnel on 317 national highway. The results show that( 1) the particle size is disparity and farraginous,the surrounding rock's variation is drastic and vertically,it is mainly divided into the layer containing sand gravel with ice water product and the layer with ice boulder gravels;( 2) the composition and distribution of surrounding rock in horizontal are the principal influence factors for the axial force of anchors,the contact pressure change and distribution between surrounding rock and primary bracing;( 3) the three-step coresoil method is safe and controllable for outwash accumulation tunnel construction.