土石坝渗流分析是大坝渗流安全评价和渗控方案设计的重要依据。根据海南省三亚市西部的宁远河中下游河段的大隆水利枢纽工程土石坝振冲填筑施工特点，利用饱和-非饱和三维渗流理论，分析了土石坝体在不同工况下的渗流场。将结果与材料各向异性时的渗流场进行对比分析后发现：对于无基坑振冲碾压土石坝来说，分层碾压造成的坝体材料渗透性各向异性特征，对渗透系数较小的防渗区土料影响较大，出现坝体上游防渗土料的渗流速度增大而坝体中部防渗土料的渗透速度降低的现象；且材料各向异性使整个断面的渗流量有较为明显的降低；坝内孔隙水压力分布主要与上游水位高度密切相关，且大坝上下游水位差越大，坝内流速和流量就越大。

Seepage analysis of earth dam is the important basis for the evaluation of seepage safety and scheme design of seepage control. According to the vibration filling construction characteristics of the earth dam of Dalong water-control project in the middle and lower reaches of Ningyuan River in Sanya city of Hainan Province, the seepage fields of earth dam under different working conditions were analyzed based on the three-dimensional saturated-unsaturated seepage theory. The seepage fields based on the anisotropic and isotropic material permeability were compared and the results showed that (1) as for the earth dam under vibration compaction without foundation pit, layered compaction can cause the anisotropic material permeability, which can have greater impacts on the anti-seepage earth material with lower permeability and result in the phenomenon of increasing seepage velocity in the anti-seepage material upstream of earth dam and decreasing seepage velocity in the anti-seepage material in the middle stream of earth dam; (2) anisotropic material permeability can lower the seepage discharge significantly across the entire section of earth dam; and (3) distribution of pore water pressure in the earth dam is closely related to the upstream water level, and the seepage velocity and seepage discharge in the earth dam is affected by the difference of upstream and downstream water levels.

湖北省教育厅重点科研项目（D20121303）资助