长江漫滩地区深基坑施工对盾构隧道影响及应急保护研究

为研究长江漫滩地区深基坑工程对邻近盾构隧道的影响因素,验证在该特殊土层实施针对性综合保护应急措施的可行性,以长江漫滩地区深基坑工程盾构隧道应急保护实际案例为背景,依据前期施工阶段监测资料,分析出该地质条件下深基坑施工对周边盾构隧道结构变形的主要影响因素为降水、侧向卸载及附加荷载。采用修正惯用法对各影响因素进行定量分析,针对后续施工叠加影响采取相应施工控制及隧道加固等综合保护应急措施。实施处置措施前后监测数据对比及反分析得出,长江漫滩地区邻近盾构隧道深基坑在设计、施工期间应着重对基坑降水、卸载及附加荷载进行控制,当盾构隧道出现结构安全问题时,采用综合保护应急措施可取得显著治理效果。

Study of Influence of Deep Foundation Pit Construction on Adjacent Shield Tunnel in Floodplain Area of Yangtze River and Emergency Protection Measures

The influence of deep foundation pit construction on adjacent shield tunnel in floodplain area of the Yangtze River is studied so as to verify the feasibility of the comprehensive emergency protection measures adopted. According to the monitoring data collected during previous construction phase, it is showed that the main influencing factors of deformation of shield tunnel structure are dewatering, lateral unloading and additional loading of deep foundation pit. The influencing factors are quantitatively analyzed by modified traditional method; and then relevant construction control technologies and reinforcing technologies are adopted. The comparison between monitoring data before and after carrying out countermeasures shows that the control of dewatering, unloading and additional loading are the keys to design and construction of deep foundation pit adjacent to shield tunnel and the comprehensive emergency protection measures adopted are rational and effective.