高渗透地层基坑工程坑底渗水处理施工实践

Construction Practice of Bottom Water Seepage Treatment of Foundation Excavation Engineering in High Permeability Stratum

项目地下水位高、地基土层较差、局部呈砂质、基坑南侧存在排水明渠等复杂地质条件,在清槽阶段,开挖电梯底坑、消防泵坑等标高较低部位时出现分层渗水甚至塌土的情况,致使底坑无法满足设计要求,严重影响底板及后续施工进度。对此,针对不同处理措施进行研究,最终按照水力学降排水“漏斗”原理,并结合阶梯形混凝土现浇圈梁填充的综合施工技术,有效解决了上述问题,确保底板施工在雨季情况下顺利完成浇筑,加快了施工进度,且后期电梯底坑等部位未出现渗水、开裂等现象,处理效果明显。

In view of the complex geological conditions such as high groundwater level,poor foundation soil layer,sandy local area,and the presence of drainage open channels on the south side of the foundation excavation,in the dredging stage,stratified seepage or even soil collapse occurs when excavating the lower elevation parts such as elevator bottom pit and fire pump pit,which makes the bottom pit unable to meet the design requirements and seriously affects the floor and subsequent construction progress.The construction research is carried out according to different treatment measures.Finally,according to the funnel principle of hydraulic dewatering and drainage,and combined with the comprehensive construction technology of filling and shearing resistance effect of step-like concrete cast-in-place ring beam,the above problems have been effectively solved,the pouring of the bottom plate construction has been successfully completed in the rainy season,and the construction progress has been accelerated.No seepage and cracking in the bottom pit of the elevator occurs in the later period,and the treatment effect is obvious.