Prediction Of Soil Erosion On Xinhe Expressway Slope

Xinhe expressway is located in the southern mountainous area of Yunnan Province,due to heavy rainfall and the complex terrain,the soil erosion on the slope is very serious.And thus often brings huge economic losses of property and jeopardizes the Xinhe expressway's operational security,so the prediction of soil erosion plays a very important role in preventing the damage caused by soil erosion.At present,there is no universally accepted soil erosion prediction method for the highway slope.In order to complete the prediction of soil erosion on the slope of Xinhe expressway,through field investigation of soil erosion along the Xinhe expressway,this paper used the advanced GIS technology and RUSLE model to establish the soil erosion prediction method of Xinhe expressway.The main contents and conclusions are as follows:1.Different from previous methods,such as monitoring based on point or grid,this paper used the vector slope plot as the unit to calculate the intensity of soil erosion in order to improve the prediction accuracy and ensure the convenience of data management and maintenance.Each prediction unit was composed of a single plot.The slope gradient,slope direction of each plot,the land use condition,soil type,vegetation coverage and soil and water conservation measures are basically the same.By dividing the prediction unit,the prediction results of soil erosion are more accurate and representative.2.The soil erodibility factor value along the Xinhe expressway was obtained through field investigation and experiment;through the runoff plot experiment,the m value of artificial slope was revised to 0.32,the steepness factor of the artificial slope with the slope degree of 1:1.5 was revised to 7.28,and the slope factor of the artificial slope with the slope degree of 1:1.0 was revised to 14.49,and the calculation of the terrain factor of Xinhe expressway slope was completed on the basis of highway topographic map and highway design data;through field investigation and remote sensing images analysis,the factors of slope cover and management measures of Xinhe expressway was calculated;the soil and water conservation measure factor was calculated on the basis of previous studies and field investigation.3.The historical soil erosion was simulated and predicted by inputting the historical rainfall data.Through the comparision of prediction data and the actual monitoring results,the average error of each monitoring area was 33.24 t·km-2,and the average relative error was 33.96%,the root mean square error of each monitoring area was relatively small,and the nash efficiency coefficient was 0.69.Generally speaking,the accuracy of the soil erosion prediction method used in this paper was high and can satisfy the requirements of real-time prediction of soil erosion on Xinhe expressway slope.4.The prediction of soil erosion on the slope of Xinhe expressway under the 20-year and one-year frequency rainfall conditions can be used to represent the risk of soil erosion on the slope of Xinhe expressway.The risk grade of soil erosion in each prediction unit was divided based on the natural break method.The results of risk classification can provide some reference for the soil and water conservation of the Xinhe expressway slope.However,due to the spatial and temporal distribution of rainfall is complex and variable,the results of classification can not represent the actual risk of soil erosion under each rainfall condition,it is still necessary to forecast the soil erosion in time for the safe operation of the expressway.