Research On Slope Surface Erosion Under Rainfall Of Artificial Loess Slope

This article use the Yan’an loess slope as the research object,relying on the project of "artificial stone slope stability and the protection technology research",through the indoor simulated rainfall slope erosion test,studied the loess slope erosion damage evolution process,influencing factors and mechanism under the condition of rainfall,on the basis of this,summarized and test the loess slope surface damage prevention and control measures.The main research work and achievements are as follows:(1)Through two relatively light rain strong rainfall infiltration test found that,as the slope increases,the formation of super seepage runoff time extended,at the end of rainfall,the whole water infiltration depth of the slope is controlled by slope surface rainfall per unit area.After the rain,the water infiltration depth is continue to increase,and eventually no longer increases to a certain depth,rainwater infiltration in slope body formed the water saturation line present shallow on the upper and deep on the lower.Then the soil moisture content reduce,reduce speed gradually slow down. Compare two rainfall infiltration process can also see that:the soil without antecedent rainfall in the first experiment,the rain landing slope quickly absorbed by the soil,when the slope soil are infiltrating nearly saturated,began to form a continuous slope runoff.Slope in prophase rainfall again under the condition of rainfall,slope runoff formation time shorted,runoff began to form in the soil not saturated,and because of the early stage of the soil moisture to evaporate incomplete,water infiltration depth is preliminary deepen,showed that the slope in prophase rainfall conditions of rainfall again,the slope hazard increases.(2)Through different slope rainfall erosion test of slope runoff and silt content results found that:after the stability of slope runoff,the size and slope runoff inversely proportional relationship,and silt content in the process of change has a critical slope, in this test the critical slope is 45o.Definition of slope runoff rate to characterize the rain area total rainfall in the proportion of rainfall runoff,the study found that the changing trends are synchronous of slope runoff rate and silt content,both are largest when slope of 45o,decrease in both sides.(3)On the observation and study of the whole process of loess slope surface rainfall erosion damage,slope erosion can be divided into four stages:splash erosion,infiltration, surface erosion and collapse.The slope erosion damage formation mechanism under the heavy rain can be divided into rainfall hit impact mechanism, water softening mechanism and groove cutting mechanism,three kinds of mechanism in the process of rainfall in turn,promote the development of the loess slope surface erosion.(4)Based on the summary of loess slope surface protection measures and its existing problems,targeted to choose different protection measures to test study,the experimental results show that:to set up the intercepting and gully trough the slope,stainless steel net platform slope shoulder,laid with dust as a transitional contact zone between the concrete and the loess and the method of planting perennial ryegrass protective effect is good,can guarantee the stability of slope surface as a whole.