Abstract: Abstract：The working behavior of single pile with verical load in subsidence area during groundwater recession was studied through theoretical analysis．Based on the single-phase floWhypothesis and the Bishop unsaturated effective stress principle，a mathematical model which could reflect the settlement in both saturated zone and unsaturated zone was established incorporating the linear soil and water characteristic curve．Assuming that the load transfer function was ideal elastic-plastic for the pile- soil interface，shear strength of which increasing with depth，and hyperbolic model for pile endpoint，then，Q-Scurves，side friction stress along the pile were analyzed according to the shear displacement method during waterlevel fal1

Key words: waterlevel fall, saturated unsaturated settlement, negative friction, shear stress pat

摘要： ：针对地下水开采引起的地面沉降区段，研究了降水沉降对竖向受荷桩基的影响。基于单相流假设和Bishop 有效应力原理，结合简化的直线型土水特征曲线，建立了反映地下水位下降桩周土饱和～非饱和沉降的数学模型。 假设桩土界面极限抗剪强度随深度递增，桩土界面的荷载传递函数为理想弹塑性模型，桩端土采用双曲线模型，采 用剪切位移法计算分析了受降水沉降影响，既有桩基Q—S曲线、侧摩阻力等的变化规律。

关键词: 地下水位下降, 饱和一非饱和沉降, 负摩阻力, 剪切路径