大面积深基坑分区开挖效果分析

Effect analysis of zoned excavation of large area deep foundation pit

利用PLAXIS3D有限元软件构建基坑支护三维有限元模型,模拟大面积深基坑不同分区开挖方式对围护结构以及邻近隧道变形的影响,结果表明大面积深基坑分区开挖对围护结构和邻近隧道变形有较大影响,分区越多,围护结构变形越小。因此选用对基坑进行分区开挖的方案二作为施工方案。经对比数值模拟结果与实际工程监测结果,基坑分区开挖能有效控制围护结构以及邻近隧道变形,且数值模拟结与实际监测数据的变形趋势一致。分析结果为大面积深基坑开挖方式选择提供了参考。

By using PLAXIS3D finite element software, the three-dimensional finite element model of foundation pit support is constructed to simulate the influence of different partition excavation methods of large-scale deep foundation pit on the deformation of retaining structure and adjacent tunnels. The results show that the partition excavation of large-scale deep foundation pit has a great influence on the deformation of retaining structure and adjacent tunnels. The more partitions are, the smaller the deformation of retaining structure is. Therefore, the second scheme of partition excavation of foundation pit is selected as the construction scheme. By comparing the numerical simulation results with the actual engineering monitoring results, the partition excavation of foundation pit can effectively control the deformation of retaining structure and adjacent tunnel, and the numerical simulation results are consistent with the deformation trend of actual monitoring data. The analysis results provide a reference for the selection of large area deep foundation pit excavation methods.