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

采用有效应力迭代算法来确定中性点位置和计算下拉荷载值,并通一个实例来说明迭代试算。

The diagnosis principle and diagnosability conditions are proposed, and the normal tolerance network test nede voltage interval are given by interval iterative algorithm.

方法给出了差情况下诊理和可诊性条件，并利用区间迭代算法，给出了差网络无故障情况下测试节点电压范围。