Study On The Law Of Slope Surface Slip And Rainfall Warning Value Of Railway Subgrade Slope

Railway flood control is an important aspect to ensure the safety of transportation in flood season.In 2018,China's railways achieved the eighth consecutive year of flood control safety,with hard-won achievements,but there are still many problems in flood control work.In this paper,based on the "research on the early warning and protection technology of the influence of rainfall erosion rule and shallow slip collapse on railway subgrade slope"(China academy of railway sciences foundation,2017YJ035),the south section of Xiangyang-Chongqing railway is taken as an example to conduct research in two aspects: In the area where the historical rainfall data is scarce,the calculation method of the hazard degree of slope collapse is put forward by using the parameters easily available on site;In the area with sufficient historical rainfall data,the method of making scientific rainfall warning index and its value is put forward.Specifically,the research work and results of this paper are as follows:(1)A full investigation was carried out on the south section of Xiangyang-Chongqing railway to analyze the rainfall characteristics of "autumn rain of West China" in the flood season along the railway and the significant difference between the number of field rainfall and the accumulated rainfall.The main disaster types in the flood season in each section of the railway are assured.it is pointed out that slope surface slip is the main disaster type in the flood season of the railway,and the spatial and temporal distribution of slope surface slip is analyzed.Taking three typical disaster sites as the research objects,this paper analyzes the reason why south section of therailway is prone to slope surface slip collapse.(2)By using the method of indoor geotechnical test,the liquid plastic limit test,direct shear test and falling head permeability test were carried out on the slope soil of typical slump site.The mechanical and hydrological effects of slope vegetation on slope soil were analyzed.(3)The influences of slope slope,rainfall characteristics,initial moisture content and soil properties on infiltration rate,cumulative infiltration amount,infiltration depth and wetting front advance velocity were calculated and analyzed by using the improved Green-Ampt model.By using SEEP/W and SLOPE finite element and SPSS multiple linear regression,the effects of soil factors,rainfall factors,SLOPE geometry size,SLOPE vegetation cover status and other factors on the shallow slump disease were analyzed.(4)The limitation of the present railway flood control management system is analyzed.the sourth section of Xiangyang-Chongqing railway statistically analyzed rainfall data from 2015 to 2017,will be divided into the railway as Wanyuan-Maoba and XuanHan-dazhou and taking effective rainfall model based on 1 h maximum rainfall as rainfall warning index,put forward to develop suitable for sliding collapse disease science rainfall warning indicators and methods of the value.