The effective stress iterative method of estimating neutral point and downdrag on a single pile was presented in this paper.

采用有效应力代算法来确定中性置和计算下拉荷载,并通过一个实例来代试算过程。

Analysis results show that location of pile neutral point is the lowest and downdrag caused by NSF is maximal if neglecting working load on pile top.

分析结果表，不考虑桩顶荷载中性置是最低，下拽力是最大。