山岭隧道原位扩建工程监测数据分析研究

Study on monitoring data of in-situ extension of mountain tunnel

为研究山岭隧道原位扩建工程中的围岩变形规律,分析不同开挖方式,依托福州马尾隧道(北洞)原位扩建工程,分别对隧道进出口段拱顶下沉、周边收敛、和围岩体内位移进行现场监测。通过对两个开挖方式不同的断面监测数据对比分析,研究不同开挖方式对隧道围岩变形的影响。研究结果表明,上台阶左右侧分步开挖可以有效减少拱顶沉降变形,上台阶开挖对围岩扰动较大,主要表现为上台阶开挖时拱顶下沉增长较快;而下台阶开挖时,拱顶沉降速率逐渐趋于平稳。

In order to study the deformation law of surrounding rock in the in-situ extension project of Shanling tunnel and analyze different excavation methods,this paper,based on the in-situ extension project of Mawei Tunnel(North Cave)in Fuzhou,conducted on-site monitoring of arch roof subsidence,peripheral convergence and internal displacement of surrounding rock in the entrance and exit section of the tunnel.By comparing and analyzing the monitoring data of two sections with different excavation methods,the influence of different excavation methods on the deformation of surrounding rock is studied.The results show that the excavation on the left and right side of the upper step can effectively reduce the settlement deformation of the vault,and the excavation on the upper step has a greater disturbance to surrounding rock,which is mainly manifested in the rapid increase of the vault settlement when the upper step is excavated,while the settlement rate gradually becomes stable when the lower step is excavated.