地铁咽喉区小间距隧道施工围岩分析

Study on surrounding rock deformation of small-spacing tunnels in throat area of metro parking lot

深圳地铁8号线望基湖停车场咽喉区段,与之相连的有出场线和入场线2条单洞单线隧道,2条隧道以2.59 m的小间距并行施工,具有较大的施工难度和风险。通过建立三维数值模型,模拟现场施工作业,并将计算结果与现场监测结果进行对比,分析围岩的变形情况。研究结果表明:从位移方面看,拱顶沉降和水平收敛与监测结果相比相差不大,小间距隧道中间岩柱稳定性较好。小间距隧道围岩变形值都处于正常范围内,施工现场安全性较高,现场施工作业继续按目前的施工工序进行,便可在规范要求下完成施工。围岩变形的控制,在于合适的隧道开挖方式以及开挖后较强的早期支护和必要的辅助支护措施。

Two single line tunnels are connected with the throat section of Wangjihu Park,which is part of Shenzhen Metro Line 8.These Double-hole parallel tunnels are constructed at 2.59-meter intervals.Hence,this project is implemented with great construction difficulty and high construction risk.To analyze the deformation law of surrounding rock for tunnels,a 3D numerical model has been established to simulate the process of construction on site,and the obtained results are compared with field tests in this paper.The results show that the settlement and horizontal convergence of vault are close to those of monitoring results in terms of displacement,the middle rock column of small-spacing tunnels is in good stability.It can be observed that the total soil deformation of surrounding rock is within the normal range.The project can be completed in accordance with the requirements of specifications following the current construction process.The presented numerical simulation method can be used to provide references for guiding construction and evaluating construction safety.The control of the deformation of the surrounding rock lies in the way of tunnel excavation and the strong early support and necessary supporting measures after the excavation.