Research On The Rules And Evaluations Of Water Erosion On Railroad Slopes

With the gradual increase in scale of transportation construction,harmonious and sustainable development of traffic and environment has been put on the agenda.Soil erosion is one of the important contents in eco-environment.The influencing factors of water erosion on railroad slopes are complicated.The research on water erosion process, erosion mechanism and influencing rules of each factor is still relatively backward. How to make an accurate assessment of water erosion is a main content in environmental evaluation of railway.It is a difficult problem to discover the water erosion rules and to put forward reasonable suggestions for design and research in engineering.Water erosion on railway slope will be the significant theory and technical issue.This dissertation is combined with the project "Research on Key Indicators of Impact on Ecological Environment caused by Railway Construction"(commissioned by Technology Division Ministry of Railways in Oct.2005).The research work in this dissertation is based on investigation results of water and soil loss and experimental data of water erosion obtained by Ecological Environment Research Center of Beijing Jiaotong University.Research and discussion are systematically carried out on erosion test of individual railfall,the process of water erosion,the rule of influencing factors, erosion calculation model,evaluation method of water erosion and preventive measure of railway slope.In this research,field experiment,theoretical analysis,numerical calculation and evaluation method are used.The main research contents and achievements are as follows:(1) In black soil region of Northeast China,red soil region of South China and loess region of Northwest China,typical railway slopes are selected for runoff plots experiment of natural railfall erosion and gully erosion.The artificial rainfall experiment in rock area of Southwest China and North China is supplemented.The annual erosion scope of different railway slopes is presented.(2) The rules of individual railfall erosion and influencing factors of water erosion for various railway slopes are presented.The research is based on the experimental data analysis of natural railfall and artificial railfall erosion on embankment slope,cutting slope,spoil site slope,construction camp slope and road slope in Yongtaiwen Railway, Qinhuangdao-Shenyang Railway and Neijiang-Kunming Railway.(3) Analysis work is done on individual Rainfall infiltration and motion equation of slope runoff.Equation of soil erosion ratio is established.The calculation model of water erosion is proposed.Influence rules are summed up on runoff time,production flow and erosion rate.The influencing factors are analyzed such as rainfall intensity, permeability coefficient,soil suction,compactness,water content,manning roughness coefficient,slope gradient and slope length.(4) Evaluation system of railroad slope erosion is presented.The following contents are proposed in this dissertation:evaluation methods,evaluation criteria aiming at the rainfall erosion and the annual-rainfall erosion,and the variation relationship of the individual-annual rainfall criteria.Furthermore,the acceleration method and calculation method of railroad slope erosion based on practical work are put forward.(5) Measures are taken to prevent soil erosion,according to the preventive effect and evaluation criteria of rainfall erosion,suggestions of protective measures on subgrade slope are presented.