软土地区临河基坑支护的变形监测及环境影响分析

Analysis of the environmental impact of the foundation pit adjacent to a river in soft soil area by deformation monitoring

通过分析某软土地区临近河道斜抛撑基坑的施工全过程监测数据,归纳了支护桩顶水平位移、坑外地表沉降及河道防汛墙水平变形随施工时间的变化规律,初步定量分析了坑边留土面积对支护桩顶水平位移和坑外地表沉降的影响。通过比较两种拆撑工序的变形监测数据,探索了一种与常规斜抛撑拆撑工序不同的方式,采用这种方式的支护桩顶水平变形比采用常规方式的小50%。所得结论为此类基坑的设计和施工提供借鉴和参考。

By the analysis of the monitoring data through whole excavation operation for the foundation pit which not only is adjacent to a river in soft soil area but also uses inclined braces as its supporting system,this article concludes the with-time variation of horizontal displacement on top of supporting piles,ground surface settlement around pit,and horizontal deformation of flood prevention wall alongside the river.The article makes preliminary quantitative analysis for the impact of retaining soil area alongside pit on horizontal displacement on top of supporting piles and ground surface settlement around pit.Through the comparing analysis of the deformation monitoring data,a new brace-removing process is introduced in comparison with the common process,and the conclusion is drawn that horizontal displacement on top of supporting piles is reduced by 50%in use of the new process.The results can provide a reference for the people who do the design and construction work on those similar foundation pits.