Evaluation Of River Slope Stability Zoning And Optimization Of Treatment Scheme Based On UAV Tilt Photography

The Loess Plateau is one of the four major plateaus in China.Due to its special soil structure,it has gradually formed a landform of thousands of gullies in the long history of rain and river erosion.Due to the long-term erosion of running water,the river is cut down,and a relatively high and steep unstable slope is formed on both sides of the river.This slope is prone to collapse and slide under the continuous erosion of running water,which seriously threatens the life and property safety of residents on both sides of the river.Therefore,it is necessary to harness the river slope on the Loess Plateau.However,in the existing governance process,geological survey takes a long time and consumes a lot of manpower and material resources.At the same time,there are some irrationalities in the method of scheme comparison and selection based on the existing technical means.Therefore,it is very necessary to use new technology to carry out geological survey and improve the traditional method of scheme comparison and selection.In this paper,the riverway slope of limashagou in Lanzhou is taken as the research object.Firstly,the image data of the study area is collected by using the UAV tilt photography technology.Based on the processed high-definition image map and the topographic data processed by Arc GIS,the riverway slope is partitioned and evaluated to evaluate the stability of each section of the slope,so as to reduce the time of on-site geological survey and improve the work efficiency;Secondly,the slopes in the study area are classified into four types: steep up slope and gentle down slope,gentle up slope and steep down slope,compound slope and smooth down slope.Most of the river slopes in the study area have been deformed,and the slopes with larger average slope are mainly compound slope and steep up slope and gentle down slope,The overall average slope of composite slope is more than 50 °,The slope aspect is roughly perpendicular to the river trend,and the slope on the left bank is close to the buildings with poor stability.After that,the traditional TOPSIS method is improved,and the quadratic projection area is used to replace the original Euclidean distance,so that each scheme can be sorted more effectively.The improved TOPSIS method solves the problem that the traditional TOPSIS method can not be sorted because of the same calculation results,and improves the critical weighting method,and uses the ratio of standard deviation and average value to replace the standard deviation when calculating the variability,At the same time,the critical weighting method is used to solve the problem that TOPSIS does not consider the correlation of indicators;Finally,the improved critical-topsis method is used to compare and select the schemes for the slope treatment project of Lanzhou limashagou river course,and the best scheme is the reinforced earth retaining wall + retaining wall scheme.