Model Test Study Of The Hydrological Effect Of Slope Vegetation Under The Action Of Artificial Rainfall

Hainan island is very rich in forest resources, has highest forest coverage. But with the development of economy in recent years, human engineering activities and mountain forest economic crops caused varying degrees of destruction of slope vegetation in mountainous area. Caused by the typhoon heavy rain weather, there is a large number of small slope instability phenomenon appeared in the vegetation destruction area. These small slope failure pattern is most slope surface erosion and shallow under the action of rainfall. Although the personal injury and property loss caused by those slope failure is not huge, but the slope failure bring so much inconvenience to the tourism traffic and tourism.So this paper focus on the perspective of ecological slope protection, study the hudrological effect of slope vegetation under the rainfall and explore the mechanism of the vegetation slope protection.Slope model test of artificial rainfall is presented in this paper. Model formed by floury soil from Haikou Meilan District, the vegetation of the test model is bare soil, Tuberous Sword Fern Rhizome and thin leaf zoysia. The monitoring system in test model can collect and measure the slope surface runoff, real-time monitoring the rain osmotic quantity and the soil moisture change in slope.The Firs step, study the floury soil indoor test. Including the determination of physical properties index and the shear strength index of unsaturated floury soil influence by saturation. Experimental results show that the peak shear strength of unsaturated floury soil occurs in the saturation is about50%, decreases with the increase of saturation higher than50%, decreases with the loss of the saturation less than50%. Due to the special properties of the floury soil, high apparent cohesive force will appear in the process of natural dehydration.By comparison of three different vegetation situation of slope model in twice artificial rainfall. Learned that slope vegetation hydrology effect is mainly formed by intercepting rainfall to surface runoff, changing the rain infiltration path, influence the permeability of slope soil to protect slope. Slope vegetation characteristics of different plants, play a different role of ecological slope protection. Thin leaf zoysia slope protection effect formed by intercepting rainfall surface runoff, changing the rain infiltration path; Tuberous Sword Fern Rhizome slope protection effect mainly by changing the rainwater infiltration path, influence the permeability of soil slope. The damage of bare soil slope in the process of two different intensity rainfall including deformation, splash erosion and slope erosion. Comprehensive analysis shows that slope vegetation can play their own hydrological effect to avoid rain wash directly, slow slip surface of soil in the process of rainfall. The presence of vegetation will improve the slope body moisture content which affect slope soil shear strength to enhance the stability of slope.