侧摩阻力约束下降水引起的地面沉降估算方法

Estimation Method for Surface Subsidence Induced by Dewatering under the Constraint of Lateral Friction

将用于桩体负摩阻力分析的剪切位移法引入基坑降水引起的地面沉降计算中,研究了降水过程中止水帷幕与土体交界处的侧摩阻力对土体沉降的约束机制,以及侧摩阻力在土体中水平方向的传递规律,推导了侧摩阻力对土体沉降的约束位移,提出了考虑侧摩阻力影响的地面沉降量估算方法.实例分析结果表明:侧摩阻力对土体沉降的约束作用主要局限于距止水帷幕18m的范围内;在土体与止水帷幕交界处,侧摩阻力对土体沉降的约束作用最显著;所提出的考虑侧摩阻力作用的地面沉降计算方法能够很好地预测降水期间地表沉降量的分布.

Based on the shear displacement method used in the negative skin friction calculation of pile, this paper analyzed the constraint mechanism of lateral friction located in soil-waterproof curtain interface to wards soil settlement as well as its horizontal transfer law in soil during engineering dewatering. Then, the constraint displacement was deduced. Finally, a novel calculation method for soil subsidence estimation in- duced by dewatering consideration the effect of lateral friction was put forward. The research results show that the constraint function of lateral friction to soil settlement is mainly limited in the range of 18 m away from the waterproof curtain; the position where the constraint effect of lateral friction became most signifi- cant was at the interface of soil and waterproof curtain. The novel estimation method proposed taking the lateral friction into account can well predict the space distribution of soil subsidence induced by dewatering.