城际轨道深基坑支护优化及实测分析

Monitoring Analysis of Ultra-deep Foundation Pit With Optimized Support Scheme in Intercity Rail Engineering

为研究莞惠城际轨道基坑施工方案的可靠性,结合莞惠城际轨道工程深基坑开挖的具体实践,基于现场实测数据,对深基坑开挖过程中桩体水平位移、桩顶水平位移、地表沉降、支撑轴力、地下水位变化规律进行了全面深入的研究.结果表明:降水对地表沉降有较大影响,施工中应予以重视;钢支撑的预应力对基坑的变形特别是围护结构侧向位移控制有较大影响;钢支撑轴力远小于设计值,设计方案可以进一步优化;优化后的支护方案较好地限制了基坑变形.

Guanhui intercity rail foundation pit was a ultra-deep foundation pit constructed by the optimized support scheme. Based on the monitoring data,the authors studied the horizontal displacement of the pile,horizontal displacement of the pile top,ground settlement,strut axial force,groundwater fluctuation regularity during the process of excavation comprehensively and thoroughly. The results show that dewatering has a great impact on ground settlement which should be paid attention in construction;the steel support prestress has a great influence on foundation pit deformation,especially on the lateral displacement of the pile; steel support actual axial force is much smaller than the design value,the design scheme can be further optimized; and the optimized support scheme has limited the deformation of foundation pit very well.