The Outdoor Experiments And Numerical Analyses Of Non-orthogonal Rainfall Infiltration On Surfaces Of Unsaturated Slopes

At present,the unsaturated soil seepage analysis are disposed of in accordance with the second boundary of the traditional slope rainfall infiltration problem,again after the rain according to the slope direction orthogonal decomposition orthogonal infiltration,to satisfy the mathematical principle of traffic flow.Based on the actual rainfall observation,it can be found that orthogonal infiltration of rainfall is far from simple like that.In this paper,the main content is the outdoor experiments and numerical analysis.Comparing the results between the outdoor experiments and numerical analysis,it could obtain the infiltration boundary conditions for unsaturated soil slope.In the outdoor experiments,the variable Angle outdoor test device was used respectively for unsaturated soil,silty clay and silt.With the Artificial simulation of rainfall device,it could research the affection of the void ratio and the slope Angle to the outdoor experiments.Besides,the outdoor experiments obtained the moist peak movement,which could observe internal rule of rainfall infiltration in unsaturated silt.In the numerical analysis,SEEP/W was used to establish the model for numerical analysis.SEEP/W adapts the second boundary conditions,and it would reveal the defects of the orthogonal infiltration boundary conditions by comparing results the between the outdoor experiments and numerical analysis.Comparing the results between the outdoor experiments and numerical analysis,it can be conclusided that:1.The outdoor experiments of unsaturated silty sand,silt and clay did not conform to the traditional orthogonal infiltration boundary conditions.There was not any runoff in experiment outside for the unsaturated sand slope,which was different from the result of the numerical analysis in SEEP/W.Comparing the experiment outside and the numerical analysis in the unsaturated silt slope,the slope runoff from the experiment was much large than the slope runoff from numerical analysis in the same conditions.For unsaturated silty clay,the runoff of the outdoor experiments is not in conformity with the rainfall amount of decomposition along slope direction,that unsaturated silty clay slope do not conform to the orthogonal infiltration boundary conditions.2.The unsaturated soil slope surface rainfall infiltration accords with nonorthogonal infiltration boundary conditions.When rainfall intensity are less than infiltration capacity,the rainfall infiltrated all.When rainfall intensity are greater than infiltration capacity,the runoff started.And the runoff from the outdoor experiments is greater than the one from the numerical analysis.