邻近机场共用排桩围护结构深基坑的变形监测分析

Deformation Monitoring and Analysis of Deep Foundation Pit of Shared Row Pile Retaining Structure Adjacent to Airport

以上海某机场基坑施工为例,对共用排桩围护深基坑进行结构计算,同时在不同施工阶段进行监测,分析基坑围护和开挖对坑外地表沉降、周边建筑物和管线沉降、地下连续墙水平位移和支撑轴力的影响。研究结果表明,在基坑开挖过程中,坑外地表沉降的形态变化从三角形到凹槽形,管线沉降变化规律与坑外地表沉降的规律具有较好的一致性。建筑物的纵墙与基坑边平行时,深基坑开挖对建筑物的影响较大,导致发生不均匀沉降,而共用围护结构可以增强相邻建筑物的稳定性和安全性。支护内力的计算结果与监测值相比偏小,坑外地表沉降的计算也与实际差异较大,共用排桩围护结构深基坑的结构计算方式与普通深基坑不同,研究成果可为软土地基共用排桩围护深基坑设计和施工提供一定的借鉴。

Using the foundation pit construction of an airport in Shanghai as a case study,a structural calculation for a deep foundation pit supported by shared row pile is conducted.At the same time,monitoring is carried out at different construction stages to analyze the influence of foundation pit enclosure and excavation on surface settlement outside the pit,settlement of surrounding buildings and pipelines,horizontal displacement of diaphragm wall and supporting axial force.The results show that in the process of foundation pit excavation,the shape of surface settlement outside the pit changes from triangle to groove,and the variation law of pipeline settlement is in good agreement with the law of surface settlement outside the pit.Moreover,when the longitudinal wall of the building is parallel to the side of the foundation pit,the excavation of the deep foundation pit has a great influence on the building,resulting in uneven settlement,but the shared retaining structure can enhance the stability and safety of adjacent buildings.The calculation results of internal force of support are smaller than the monitoring values,the calculated surface settlement outside the pit quitely differs from the actual situation,and the structural calculation method of the deep foundation pit of the shared row pile retaining structure differs from that of the ordinary deep foundation pit.The study results can provide some reference for the design and construction of deep foundation pit supported by shared row piles in soft soil foundation.