深基坑标准段伺服钢支撑的应用及优化研究

Application and optimization research of servo steel support in standard section of deep foundation pit

正由于城市化的不断深入,基坑工程也向着更深更长的方向发展,传统的支护形式已经难以满足于对周边环境影响的苛刻要求,伺服钢支撑应运而生。本文依托杭州武林门地铁站,对支撑轴力及地连墙变形的实测数据进行分析并通过建立三维结构模型对基坑工程伺服钢支撑的架设方式和支撑组合形式展开研究。结果表明:普通预应力钢支撑无法满足基坑变形的要求;不同位置处的钢支撑对地连墙变形控制效果不同,距离变形最大处越近贡献越大,反之越小;钢支撑全部施加伺服系统控制效果最佳,隔一施加次之,仅一道施加最差;引入无量纲-建筑物倾斜率w,得出减小地连墙的变形是防止周边建筑物失稳破坏的关键;最后对基坑的支护结构进行优化,给出伺服轴力阀值,满足基坑的变形要求。

Due to the continuous deepening of urbanization,foundation pit engineering is also developing towards a deeper and longer direction,the traditional support form has been difficult to meet the harsh requirements of the surrounding environment,servo steel support came into being.Based on Wulinmen Metro Station in Hangzhou,this paper analyzes the measured data of the axial force and the deformation of the ground wall,and studies the erection mode and support combination form of the servo steel support in foundation pit engineering by establishing a three-dimensional structure model.The results show that ordinary prestressed steel bracing cannot meet the requirements of foundation pit deformation;The steel supports at different positions have different control effects on the deformation of the diaphragm wall.The closer the steel supports are to the largest deformation,the greater the contribution is,and the smaller the contribution is.The control effect of servo system applied to all steel supports is the best,and only one servo system applied is the worst.By introducing dimensionless building inclination rate w,it is concluded that reducing the deformation of ground wall is the key to prevent the instability and failure of surrounding buildings.Finally,the supporting structure of the foundation pit is optimized,and the servo axial force threshold is given to meet the deformation requirements of the foundation pit.