邻近基坑同步施工相互影响实测分析

Monitoring analysis of the interrelationship of synchronous construction in adjacent foundation pit

近距离相邻基坑前后施工时,后基坑的施工相当于对前基坑周边卸载,必然会对前基坑产生一定的影响。对杭州下穿湘湖某相邻基坑工程进行施工监测,主要监测内容包括混凝土支撑轴力、钢支撑轴力、深层土体位移和地表沉降等。监测结果表明:双基坑施工与单基坑施工时深层土体位移变化等规律有明显区别,后基坑在开挖过程中会减小前基坑的支撑轴力,并使相邻基坑之间的土体向前基坑倾斜。同时双基坑与单基坑混凝土支撑受拉情况明显不同,总结并对比单双基坑工程中混凝土支撑"拉/压"轴力比,双基坑的"拉/压"比值相对单基坑更大,这与基坑土体向坑外移动相呼应。

When two adjacent foundation pits are in the process of construction,the construction of the following pit is equivalent to unloading around the first foundation pit,which will have a certain impact on the first foundation pit. The monitoring of the adjacent foundation pits which down-crossing Hangzhou Xianghu mainly includes concrete supporting axial force,steel supporting axial force,deep ground displacement and surface settlement. The monitoring results show that the deep soil displacement,etc,between the double foundation pits and the single foundation pit is obviously different. The supporting axial force of the first foundation pit will reduce during the excavation of following foundation pit,which will make the soil between the adjacent foundation pit tilt to the first foundation pit. The situation of concrete support under tension between double foundation pit and single foundation pit is obviously different. Analysis of 'Pull /Pressure'in double foundation pits and single foundation pit indicates that the ratio of 'Pull / Pressure ' in double foundation pits is bigger,this is responding to the soil of foundation pit moving outside.