Vibroflotation compaction method is one of the advanced construction methods for earth-rock dam.As the main research object in this paper

the earth dam of Dalong water-control project is located in the middle and lower reaches of Ningyuan River

Sanya city

Hainan Province.Based on the unsaturated seepage theory and finite element method

the different partitions of dam are accurately expressed and a three-dimensional model is built to simulate the seepage field of earth-rock dam

The pore pressure and the flow velocity under each water level are analyzed.The seepage safety is evaluated as well.The research results show that the upstream drainage channels are made in the vibroflotation gravel layer of dam by using the construction methods of vibroflotation compaction.Under the condition of reservoir water drawdown

the direction of effective seepage velocity and seepage pressure in impervious soils are obviously reversed from the approximate horizontal to the straight downward

meanwhile

the increasing of effective seepage velocity leads to more water drainage from vibroflotation gravel layer.In a word

the construction methods of vibroflotation compaction are of benefit to the dam safety.