软土地区相邻基坑开挖时序对围护变形影响的数值分析

Numerical Analysis of Influence of Excavation Sequence of Adjacent Foundation Pit on Deformation of Retaining Support in Soft Soil Area

为解决相邻基坑开挖时序的问题,以上海某相邻基坑为例,对于施工的先后顺序进行分析论证,通过有限元模型试算4种工况下围护变形情况,经过工况间对比、与设计报警值对比之后得出最优工况,并将其作为实际工况与实际监测值对比。结果表明:基坑内侧围护结构受不同开挖工况的影响较大,外侧围护结构几乎不受影响,但外侧围护位移整体比内侧位移大;采用同步开挖时,内侧围护结构产生的位移最小。模拟结果与实际监测数据结果呈现一致性,验证了模拟的可行性,可为类似项目提供参考。

In order to solve the problem of the excavation sequence of adjacent foundation pits,taking an adjacent foundation pit in Shanghai as an example,the construction sequence is analyzed and demonstrated.The deformation of the retaining support under four working conditions is calculated through the finite element model.After the comparison between working conditions and the design alarm value,the optimal working condition is obtained and compared with the actual monitoring value as the actual working condition.The results show that the inner retaining support structure of the foundation pit is greatly affected by different excavation conditions,and the outer retaining support structure is almost unaffected,but the displacement of the outer retaining support structure is larger than that of the inner retaining support structure.When synchronous excavation is adopted,the displacement generated by the inner retaining support structure is the minimum.The simulation results are consistent with the actual monitoring data,which verifies the feasibility of simulation and can provide reference for similar projects.