不同岩性分界面位置对隧道初期支护的影响

银(川)西(安)高速铁路贾塬隧道三次长距离穿越不同岩性接触带,严重影响施工进度。本文建立三维数值计算模型,并结合现场监测数据,分析红黏土与砂岩夹泥岩分界面位于隧道不同位置时支护结构的位移及应力变化规律。研究结果表明:随着分界面从隧道顶部下移至隧道底部,拱顶沉降和拱腰水平收敛均逐渐增加,仰拱处初期支护应力逐渐增大;初期支护薄弱点在中上台阶。

Influence of Different Lithologic Interface Location on Tunnel Primary Support

The Jiayuan Tunnel of Yinchuan-Xi an high speed railway passes through long distance different lithologic contact zones three times which seriously affects the construction progress.In this paper a three dimensional numerical calculation model was established and the displacement and stress variation laws of the support structure were analyzed when the interface between red clay and sandstone mudstone is located at different locations of the tunnel.The research results show that as the interface moves down from the top of the tunnel to the bottom of the tunnel the settlement of the vault and the horizontal convergence of the arch waist increase gradually and the primary support stress at the inverted arch increases gradually.The weak point of primary support is on the upper and middle steps.