二元地基基坑降水结合悬挂式防渗墙及回灌一体化技术

Integration Technology of Combining Binary-layer Foundation Excavation Dewatering with Suspended Cut-off Wall and Recharge

通过构造基坑降水三维概化模型,利用有限元软件FLAC3D分析悬挂式防渗墙和回灌对基坑坑外的水头和地面沉降影响,主要将基坑直接降水工况、设置防渗墙的基坑降水工况和设置防渗墙及回灌井的基坑降水工况进行对比分析.分析结果表明防渗墙和回灌井,可明显提升坑外水头,有效降低了坑外沉降,减小软土层的单位沉降值,对粉砂层和细砂层的单位沉降值影响很小.同时,对比三种工况下的倾斜比,说明了距离防渗墙与回灌井越近,不均匀沉降越小.

In this paper, a generalized model of the typical cross-section is used to study the consequence of excavation dewatering with suspended cut-off wall and recharge well which have some effects on water head and ground subsidence which is outside of excavation. The comparisons of the condition of excavation direct precipitation, the condition of cut-off wall excavation precipitation and the condition of cut-off wall and recharge well excavation dewatering are analyzed. The result shows that suspended cut-off wall and recharge well can significantly enhance the water head and effectively reduce the settlement in the outside of the excavation, reduce the unit sedimentation of soft soil, have little effect on the unit sedimentation of silt and sand layers. Meanwhile, the comparisons of the tilt ratio of three conditions indicate the distance away from cut-off wall and recharge well closer, the smaller the differential settlement.