中文摘要：

由于城市高楼密集,地铁隧道网络发达,建筑物桩基、市政管线和既有隧道等地下构筑物对新建隧道空间形成较大限制,因此施工盾构往往不可避免地叠交穿越绕行既有构筑物。尤其是上下叠交的隧道穿越存在着重大施工风险,对既有隧道的安全运营构成极大安全隐患。结合上海轨道交通工程实践,采用简化理论方法、三维有限元数值模拟方法以及现场监测方法,揭示软土城区土压平衡盾构机上下交叠穿越地铁隧道的变形规律,提出上下交叠穿越地铁隧道的盾构施工参数设定规律以及安全控制技术措施。其中简化理论方法基于Winkler地基模型,得到盾构上下交叠穿越引起的既有隧道纵向沉降的计算表达式;三维数值模拟方法优化施工方法和盾构掘进参数,分析盾构隧道以较大斜交角度上下叠交施工穿越的实际工况;现场监测方法提供土压平衡盾构机上下交叠穿越地铁隧道的变形数据以及切口土压力、同步注浆、推进速度、管片拼装高程以及刀盘扭矩等施工参数的设定规律。研究成果可为合理制定城市地铁隧道交叠穿越运营隧道的保护措施提供一定理论依据,也可为其他类似多线叠交盾构隧道穿越工程提供一定的施工借鉴和参考。

英文摘要：

Building piles,municipal pipelines,existing tunnels and other underground structures have hindered the construction space for the new tunnels because of dense city buildings and developed networks of existing subway tunnels. Then the new tunnels often inevitably overlapped cross and bypass cross the existing structures. Significant construction risks will be encountered during the complex above and down overlapped construction, and potential safety hazard will also be existed in service for the existing tunnels. Based on the tunneling case for Shanghai railway transportation line,the deformation prediction of subway tunnel in service induced by EPB shield in soft clay during above and down overlapped traversing process and its construction control are presented by using simplified theoretical method , 3D finite element(FE) numerical simulation method , and in-situ monitoring method. The simplified theoretical method is originated from the Winkler foundation. The longitudinal settlement equation for existing tunnels due to above and down overlapped construction is obtained. The 3D numerical simulation method can optimize the construction scheme and shield excavation parameter. The practice case for above and down overlapped crossing with large oblique angle are analyzed. The in-situ monitoring method can obtain the measured data for subway tunnel in service induced by EPB shield and the setting rules of shield tunneling parameters,including earth pressure for cutting open,synchronized grouting,propulsion speed, segment assembling elevation,and cutter head torque. The proposed method may provide a theoretical basis for proposing correctly protective measurements of subway tunnels in service due to tunneling excavation during overlap traversing process. Furthermore,the research results can provide references to the future construction of other similar projects such as subway tunnels multi-line passing through existing structures.