南京地区基于地铁隧道保护要求的基坑变形控制指标

Deformation Control Indicator for Deep Foundation Pit Based on Subway Tunnel Protection Requirements in Nanjing Area

摘要:

为了保障南京软土地区深基坑开挖时邻近地铁隧道安全，有必要提出基于地铁隧道保护要求的基坑施工变形控制指标。基于南京某深基坑工程，开展三维有限元数值模拟，研究了软土深基坑开挖对邻近地铁隧道变形的影响规律。系统性探讨了地铁隧道与基坑相对位置变化条件下隧道变形响应特性，进而提出地铁隧道最大水平位移计算公式。根据地铁隧道保护要求，划分了基坑开挖对隧道的影响区，从而提出基于地铁隧道保护要求的基坑围护水平变形控制标准。

Abstract:

In order to ensure the safety of adjacent subway tunnels during deep foundation pit excavation in Nanjing soft soil area， it is necessary to propose control indicators based on protection requirements of subway tunnels. Based on a deep foundation pit project in Nanjing， the effect of deep foundation pit excavation on the deformation of adjacent subway tunnels was studied through 3D finite element numerical simulation. The deformation response characteristics of subway tunnels and foundation pits under the condition of relative position changes were systematically explored， and a formula for calculating the maximum horizontal displacement of subway tunnels was put forward. According to protection requirements of subway tunnels， the impact area of foundation pit excavation on subway tunnels was divided， and then a control standard for the horizontal deformation of foundation pit enclosure based on subway tunnel protection requirements was proposed.