邻近既有盾构隧道基坑工程施工安全影响评估

Evaluation of the Impact of Foundation Pit Construction on the Safety of Shield Tunnel

拟建设基坑工程开挖深度为5.8 m,北侧围护结构紧邻盾构隧道,基于该基坑的施工过程,通过基坑工程支护结构稳定性计算,并采用FLAC 3D软件进行数值模拟,评估该项目基坑工程施工对扬州瘦西湖隧道主体结构安全性的影响。结果表明,进行第二层基坑开挖时,隧道总体变形量十分接近预警值,位移最大位置出现在隧道敞口段与暗埋段的连接部位附近,施工时应该对此处采取一定保护措施。研究结果可为类似项目工程安全评估提供有效的参考依据。

Excavation depth of the proposed foundation pit project is 5. 8 m,the enclosure structure on the north side is adjacent to the shield tunnel. Based on the construction process of the foundation pit,the stability calculation of the foundation pit engineering support structure and FLAC 3D numerical simulation are used to evaluate the impact of the foundation pit engineering of the project on the safety of the main structure of the Yangzhou Slender West Lake Tunnel. The results show that when the second layer of foundation pit is excavated,the overall deformation of the tunnel is very close to the warning value,and the largest displacement occurs near the junction of the open section and the buried section of the tunnel. So certain protection needs to be taken during construction. The results of this study can provide an effective reference basis for the engineering safety assessment of the project.