求解非饱和土堤初始浸润线的一种解析法

Analytic method to solve initial phreatic level for unsaturated embankments

土堤的非饱和非稳定渗流计算分析中,堤内初始的浸润线位置对计算结果影响很大.分析土堤受到降雨、蒸发、径流及入渗影响作用,引入平均渗透强度的概念,建立了土堤的水收支平衡模型.将前阶段土体内部的渗流场视为一个暂态稳定渗流场,推导了土堤由于长期水分运动特征引起的初始浸润线的解析解.通过对日本江户川堤防的浸润线实测值与解析解计算结果进行比较分析,得出较为合理的结果.并对长江永安堤防初始浸润线进行了计算分析.

In calculation of unsaturated unsteady seepage through embankments, the initial phreatic level affects the calculated result significantly. In this paper, an analysis is made of the effects of precipitation, evaporation, runoff, and infiltration, and a water balance model is developed for embankments by introduction of the concept of average infiltration intensity. Furthermore, an analytic solution to the initial phreatic level caused by longterm moisture movement is derived for embankments with the seepage field in the embankment taken as a transient steady flow field. The model is applied to the calculation of the phreatic level of the EDO River embankment and the Yong'an embankment, and some reasonable conclusions are drawn from a comparison of the calculated results with the measured data.