基坑上跨盾构隧道实测数据分析及保护研究

Analysis and Protection of Measured Data of Shield Tunnel over Foundation Pit

摘要:

以某绕城高速公路深基坑上跨运营盾构隧道工程案例为背景，首先以南半幅深基坑违规施工为切入点，通过现场监测、检测与三维扫描普查等实测成果，佐证违规施工对盾构隧道的不利影响程度，其次通过修正惯用法理论计算及Ansys建模分析，评估隧道结构横断面及纵断面的安全性能与安全冗余储备，再次以优化保护措施的北半幅施工为比对研究对象，通过现场实测数据证明分幅、分段、跳仓、限时开挖，增加板凳桩桩长，缩小桩间距，加大盖板厚度，实施土体填充注浆等措施可减少开挖期及工后盾构隧道隆起量，可以缩短工后隆起时间。据此，提出基坑上跨运营盾构隧道在设计、施工相关建议，为该类保护区外部作业及保护工作提供参考。

Abstract:

Compared with a circular shield tunnel, a rectangular shield tunnel has the obvious advantages in space using efficiency and subsoil environment crossing. But the difference of the cross-sectional shape and the mechanical configuration makes the shield tunneling technology also change. Based on the engineering practice of the first earth pressure balanced rectangular shield machine in China in Shanghai Hongqiao CBD, and according to the field environmental monitoring, shield attitude measurement and segment shape monitoring, the key construction technologies of axis control, segment internal diameter control in any case and environmental deformation control of rectangular shield tunnel are explored and studied. The experience and conclusion can be used for guiding the implementation of the similar projects.