Study On Soil Erosion Of Expressway Slope In Pisha Sandstone Area

Soil erosion of expressway construction has become a prominent problem in China, the study on soil erosion mechanism about road-building, and the prediction of the amount of soil erosion using a reasonable model is an essential prerequisite of water conservation. Combined with the physical and chemical properties of Pisha Sandstone, analysis the main mechanism of the Pisha Sandstone's serious soil erosion is conducted in this paper.Take an example of the highway from Dafanpu to Dongsheng, which is a section of national highway 109, and located in Pisha Sandstone distribution area, the amounts of soil erosion of highway slope under different soil conditions are estimated. The results show that under the same conditions, the maximum value of Pisha Sandstone's slope soil erosion can up to 2.06 and 4.32 times respectively of that in Loess and Sandy soil in similar areas by comparative analysis. Based on Pisha Sandstone's erosion mechanism, this paper suggests some vegetation protection technologies that are suitable for Pisha Sandstone Slope. Finally, by using the Normal Equation built for soil erodibility factor established by Wishcmeier W H to estimate the three kinds of soil erodibility factor along the Dafanpu to Dongsheng highway located in the Ordos region. The results show that the Normal Equation is suitable for estimating the value of soil erodibility factor, whereas there is relatively large estimation error for Loess and Sandy soil. We found that the main reason leading to the difference lies in the nature of the soil parameters by comparative analysis. Parameters in Normal Equation are modified by using MATLAB and we can get the calculating model of K factor suitable for the Loess and Sandy slope soil of highway.