Numerical Simulation Study On Erosion Of Excavated Loess Slope

The current research on the erosion process of loess excavated slopes is in urgent need of in-depth research.Based on the investigation of plant species in Yan’an area completed in the previous period,this paper studies the four typical erosion and siltation conditions of loess slopes through long-term field observation and measurement of several typical profiles on a loess excavation slope in Ansai District,Yan’an City.The development stage and the correlation between the erosion amount and the rainfall in each stage,compared the influence of the difference of vegetation conditions on the erosion amount of different profiles;using this slope as a prototype,based on the direct shear test,using PFC2D particle flow The software builds a model,simulates the development process of profile erosion,and compares the similarities and differences of the model erosion under different rain intensities,different durations,and vegetation conditions.At the same time,the results of field survey and measurement and numerical simulation were compared.Finally,the main factors affecting the erosion development of loess excavated slopes and the mechanism of vegetation playing a role in the erosion resistance process were analyzed.The main conclusions are as follows:(1)Due to the erosion and destruction of the slope surface by natural environmental factors such as rainfall,the erosion form of the loess slope changes continuously with the passage of time,showing a trend of accelerated expansion.Its development process can be divided into several obvious stages:surface erosion stage,rill stage,potting stage and gully stage.These four stages not only have their own distinct characteristics,but also restrict and influence each other;(2)Rainfall is one of the most important factors affecting the erosion of loess slopes.Slope erosion is positively correlated with rainfall intensity and rainfall duration.The erosion damage and soil erosion of the loess slope in Yan’an area have a typical seasonality.Summer is the key period for the prevention and control of slope erosion in the loess area of northern Shaanxi;(3)Plants are an important factor affecting the erosion and destruction of loess slopes.Under different rainfall intensities and various development stages of erosion on the slope,the soil body strengthened by the root system of vegetation under the same scouring force,its damage state is lighter than that of the soil body not strengthened by the root system;and the vegetation erosion reduction effect is in the erosion.The various development stages of erosion are different,and the anti-erosion ability of vegetation under different rainfall intensities is also different.