深基坑悬挂止水帷幕结合回灌对控制沉降数值模拟分析

Numerical simulation analysis on settlement control by recharge in deep foundation pit with suspended waterproof curtain

悬挂式止水帷幕不能完全阻隔基坑内外水力联系,此时基坑周边环境难免受到基坑降水的影响;当深基坑内降水程度较大时,为保证周边建筑安全,悬挂式止水帷幕结合坑外回灌的方案开始被用于实际工程中。文章以某深基坑工程实例为依托,利用有限差分软件FLAC3D对基坑降水工程进行数值模拟,对悬挂式止水帷幕条件下深基坑工程降水与回灌过程中的水位变化与地表沉降进行分析。研究表明,止水帷幕结合回灌的方案能够大幅减小基坑外水头降深,有效控制基坑外的地表沉降发展,对比未设置止水帷幕和回灌措施的降水方案,水头降深和地表沉降控制率可达80%以上。合理排布回灌井位置,尽早启动回灌井回灌,可使沉降控制效果最优化。

The suspended waterproof curtain cannot completely cut off the hydraulic connection inside and outside the foundation pit.If the degree of dewatering inside the foundation pit is large,the surrounding environment will still be affected.To ensure the safety of surrounding buildings,the scheme of suspended waterproof curtain combined with recharge has been used in practical projects.Aiming at a deep foundation pit project,the finite difference software FLAC3D was used to conduct numerical simulation,the laws of water head and ground settlement outside the foundation pit were obtained under the action of suspended waterproof curtain combined with recharge.Results show that the scheme of suspended waterproof curtain combined with recharge can greatly reduce the drawdown of water head and effectively control the development of ground settlement outside the foundation pit.Compared with the scheme without suspended waterproof curtain and recharge,the control rate of water head drawdown and ground settlement can reach 80%.Besides,the effect of settlement control can be optimized by arranging the recharge well position reasonably and starting the recharge well as soon as possible.