Characteristics Of Soil Erosion In Typical Engineering Accumulation In Karst Region

Engineering accumulation has become one of the important sources of soil and water loss,but its soil and water loss has certain particularity because of its special structure,complex composition and other characteristics and has been concerned by the academic community.Whether the special structural characteristics of engineering accumulations will lead to the migration of rainwater carrying soil from the pores inside the accumulations to the deep has not been studied.Therefore,this paper takes a class of typical engineering accumulations formed by linear engineering(slope-dependent dumping type)as the research object,and studies the influence on the rainfall intensity and stone content and slope of engineering accumulation through simulated rainfall experiments.Including runoff and sediment yield of surface,subsurface,underground.The results can provide theoretical reference and basis for the prediction and control of soil and water loss,and provide theoretical support for ecological restoration in the area.The main findings are as follows:(1)With the increase of rainfall intensity,the runoff of surface,subsurface and underground of engineering accumulation slope increase gradually.The runoff ratio of surface decreases with the increase of rainfall intensity,but the subsurface is opposite(except the rainfall intensity is 110 mm/h).The runoff ratio of underground decreases with the increase of rainfall intensity.The sediment yield,sediment yield rate and the modulus of sediment yield of engineering accumulations increase with the increase of rainfall intensity.The ratio of underground sediment yield is obviously larger than that of surface.The sediment yield-producing process of engineering accumulation under different rainfall intensity is increasing,decreasing and stabilizing.(2)Under the three types of gravel content,the runoff yield,runoff rate and the modulus of runoff of engineering accumulations all show that the underground >subsurface > surface.The runoff yield of surface decreases with the increase of gravel content,while the runoff yield of subsurface and underground are opposite.The runoff yield ratio of underground is the largest,the second is subsurface and the smallest is surface.The runoff-producing process of engineering accumulation under different gravel content is increases slowly,and then increases rapidly,and finally tends to be stable in three stages.The sediment yield of surface under different gravel content is less than that of underground.The sediment yield,sediment yield rate and the modulus of sediment yield of engineering accumulations decrease with the increase of gravel content.The ratio of surface sediment yield is obviously smaller than that of underground.The sediment yield-producing process of engineering accumulation under different gravel content,is increased first,then decreased,and became stable.(3)Under each grade of slope,the runoff yield,runoff rate and the modulus of runoff all show that the underground is the largest,the second is subsurface and the smallest is surface.The runoff yield of surface increases with the increase of slope,the subsurface and underground are opposite,the subsurface decreases first and then increases.The runoff yield ratio of engineering accumulations all show that the underground > subsurface > surface.The runoff yield ratio of surface increases with the increase of slope,while the underground is opposite,and the subsurface decreases first and then increases.The transition of sediment production from underground to surface when the slope is between 35° and 40°.The sediment yield of surface increases with the increase of slope,but the underground are opposite.The sediment yield of surface of engineering accumulation are all 30°<35°<40° in the whole rainfall process,while that of underground is opposite.(4)Correlation between rainfall intensity with the runoff yield of surface,the runoff yield of underground,the sediment yield of surface and the sediment yield of underground of engineering accumulation are extremely significant(p ﹤ 0.01),and significant correlation with the runoff yield of subsurface(p ﹤ 0.05).There is a negative correlation between gravel content with runoff and sediment yield of surface of engineering accumulation.There is a positive correlation between gravel content with the runoff yield of subsurface and underground and the sediment yield of underground.There is a positive correlation between slope with the runoff and sediment yield of surface.There is a positive correlation between slope with the runoff yield of the subsurface and underground,the sediment yield of underground.The quadratic function can be used to fit the rainfall intensity to the runoff yield of the surface,subsurface and underground and sediment yield of surface,and the linear relationship between the rainfall intensity and the sediment yield of underground can be well fitted.The quadratic function can be used to fit the gravel content and slope to the runoff and the sediment yield of various types of engineering accumulation.