叠交隧道短期内二次穿越施工引起的变形分析

Analysis on deformation caused by two overlapped shield tunnelling in short time

结合现场实测数据,对叠交隧道短期内二次穿越施工参数的设定、地面和先建隧道的变形规律进行了研究。结果表明:盾构在近距离上穿施工时,土仓压力、注浆压力及注浆量较常规段要大,推进速度的设定要综合考虑盾构机出土效率、注浆效果,并非越慢越好。本工程穿越施工时的设定值为40mm/min,现场实测发现变形符合设计要求。短期内二次穿越施工引起叠交区地面变形量值较常规段要大,本工程后建隧道上、下行线穿越施工引起叠交区域内最大竖向变形量分别为+7.4mm和-17.9mm,因此该区域是变形控制的重点。已建隧道的变形既包含自身的固结变形又包括后建隧道施工的扰动影响,实测变形为两者的综合,规律性不明显。

Combining with monitoring data,working parameters,groundsurface deformation and former tunnel deformation caused by two overlapped shield tunnelling in short time were analyzed.It is showed that chamber pressure,grouting pressure and grouting volume are larger than those of normal segment.The speed of shield tunneling depends on the efficiency of dumping soil and the effect of grouting.The set speed of this project is 40mm/min and the field measurements of deformation is met the design requirements.The groundsurface deformation caused by two overlapped shield tunnelling in short time is lager than that of normal segment.The maximum vertical deformations in the overlapped tunnel are ＋7.4mm and-17.9mm,so it is the emphasis of deformation control.The deformation of former tunnel includes consolidation deformation and the disturbing effect of later tunnel,and it does not have regularity.