Study On Instability Failure And Prevention Of Soil Slope In Ningde Mountainous Area

With the speed of construction of mountain roads in China,the original geological structure will inevitably be destroyed during the construction process,and various geological disasters will also increase.Among them,the instability of soil slopes in mountainous roads is particularly prominent.Landslide is one of the most common types of slope failure and has a certain impact on the construction and surrounding environment.In serious cases,it also causes heavy losses such as casualties.In Ningde City,located in the eastern part of Fujian Province in the southeast coast of China,the danger of landslide disasters in mountainous areas is increasing day by day,which seriously restricts the local economic development.Therefore,accurate analysis of the stability of highway slopes in the Ningde mountainous area,prevention and control of soil slopes is a challenging research task in the road construction of Ningde City.Based on the research results of the analysis of the stability of the soil slope of mountain roads at home and abroad and the commonly used prevention and control measures,this paper combines the engineering case of K2+590～K2+900 section of the on the ShangYangtou slope of the mountain road in Pingnan County,Ningde City,through the method of finite element numerical simulation,the stability and prevention measures of the soil slope of mountain roads in Ningde City were studied.The specific research contents and results are as follows:(1)Based on the large-scale collection and analysis of the instability data of the soil slope in the Ningde mountainous area,it is concluded that the factors affecting the stability of the soil slope in the Ningde mountainous area of Fujian can be divided into internal factors(stratigraphic lithology factors,geological structure factors)and external factors(seismic activity factors,rainfall factors,slope vegetation conditions,human activities factors).Among them,stratum lithology and rainfall are the main reasons affecting the slope stability in Ningde area.(2)Relying on a slope section of the K2+590-K2+900 section of the ShangYangtou Slope on the mountain road in Pingnan County,Ningde City,based on the limit equilibrium method(simplified BISHOP method)and the finite element strength reduction method,the stability analysis of the ShangYangtou slope under natural conditions is carried out,and the stability coefficient and sliding surface of the slope are determined.At the same time,the shape and position of the most dangerous slip surface calculated by ABAQUS finite element analysis method based on strength reduction technique are in good agreement with the limit equilibrium method,and the correctness and effectiveness of the method are verified.(3)Rich rainfall is one of the main reasons affecting the stability of mountain slopes in mountainous areas in Ningde.Based on the saturated-unsaturated theory of soil,ABAQUS finite element analysis software is used to simulate the rainfall infiltration of the ShangYangtou Slope.It mainly analyzes the influence of rainwater infiltration on the slope stability of the the ShangYangtou Slope under heavy rain conditions.The simulation calculation shows that after the rainwater infiltration,the displacement of the ShangYangtou Slope continues to increase,the stability decreases,and the slope has the hidden danger of slip instability.(4)According to the stability analysis results of the ShangYangtou Slope,combined with the actual protective measures of the slope,it is considered that the drainage method + anchoring method + supporting method is suitable for the comprehensive prevention and control of the ShangYangtou Slope.The dynamic monitoring of the Shangyangtou Slope after comprehensive prevention and control was carried out.It mainly monitors the deep horizontal displacement of the slope.According to the displacement curve,the stability of the slope is evaluated.From the measured horizontal displacement analysis data of the measured points,the displacement values are floating up and down within the controllable value.It can be confirmed that the ShangYangtou Slope is relatively stable after comprehensive protection,and the comprehensive protection scheme is reasonable and feasible.This paper has certain reference value in the stability analysis and comprehensive prevention of soil slope in Ningde mountainous area.