某既有基坑加深后围护结构加固技术

Reinforcement technology for the retaining structure of an existing foundation pit after deepening

某基坑工程有2层地下室,原设计方案采用放坡、土钉墙和拉锚式排桩墙的围护结构。在原基坑围护桩已施工完成,部分锚杆已施工,开挖至2层地下室的情况下,因规划设计调整,将2层地下室改为3层地下室,该调整会导致原围护桩形成吊脚桩。因此,在基坑原围护结构的基础上,根据现场周边环境和实际土质情况,3层地下室围护采用多种围护加固技术相结合的设计方案。监测数据表明,土体水平位移值和沉降值均满足要求,可见该既有基坑加深后围护结构加固技术是成功的,具有一定的借鉴作用。

There is a two-story basement of a foundation pit project,and the original design scheme adopts the retaining structure composed of slope excavation,soil nail wall and anchored pile and wall.When the retaining pile,part of the anchor rod and the second-story basement of original foundation pit has been constructed,due to planning and design adjustments,the two-story basement was changed into a three-story basement.This turns the original retaining pile into the end-suspended pile.Therefore,based on the original retaining structure of the foundation pit,and according to the surrounding environment and actual soil conditions,the three-story basement enclosure adopts a design scheme that combines multiple reinforcement technologies.The monitoring data shows that both the horizontal displacement and settlement of the soil meet the requirements,which proves that the reinforcement technology for the retaining structure of an existing foundation pit after deepening is successful and has a certain reference value.