基坑加固扰动引起地铁隧道隆起变形

Displacement of subway tunnels induced by above foundation pit reinforcement

针对如何控制上方基坑底部加固扰动引起下卧地铁隧道的变形、确保地铁安全运营的问题.结合上海市浦东新区东方路-张扬路地下立交工程,在考虑隧道等效刚度、施工卸荷以及加固抑制回弹的效果等因素的基础上,对上方搅拌桩施工扰动引起正在运营地铁隧道的竖向隆起变形进行了机理分析,推导出基于Winkler模型计算隧道竖向位移的方法并进行了理论计算.结果表明:上层加固扰动引起隧道的竖向位移是非常可观的,需引起足够重视.并将计算结果和实测数据进行了对比.在此研究基础上提出了一系列控制上层搅拌桩施工引起运营地铁隧道位移的施工方法.

To insure the safe operation of subway, based on data from the East Road Underpass Project, and in view of different relative locations between deep mixing piles and subway tunnels, theoretical and empirical analyses were conducted on the vertical displacement of tunnels aroused by large - scale deep - mixing - piles driving above and adjacent to the tunnels, considering the equivalent stiffness of tunnel and pile group effects. A method to calculate the vertical displacement of tunnels based on the Winkler model was derived, and the calculation was carried out. The calculation result was compared with the measured data. It is indicated that effects of above foundation pit reinforcement on the vertical displacement of tunnels are considerable. And some measures are presented to control the displacement of tunnels, in view of the influence of the number of continuously driven piles, sheltering effects, pile distance and soil character.