Study On The Development Law And Stability Of Clastic Slope In Southeast Tibet Section Of G318 National Highway

In this paper,the material structure characteristics of the debris slope in the study area are analyzed and classified according to the nature,activity and gradation of the debris slope.By studying the spatial distribution law,material composition characteristics and evolution law of debris slope and controlling the different influence factors of debris slope,the stability of debris slope is analyzed,and then the engineering risk of debris slope is predicted by using the method of fuzzy comprehensive evaluation.It is of great practical significance to ensure the sustainability and safety of the reasonable construction and operation stages of the southeast section of G318 National Highway in Tibet.The following conclusions are drawn:(1)The debris slopes in the study area can be classified into clay debris slopes,non-clay debris slopes,strong active debris slopes,medium active debris slopes,weak active debris slopes,stable debris slopes,block debris slopes and gravel debris slopes.gravel clastic slope.(2)The survey results along G318 National Highway show that the debris slopes are mainly developed in Bangda area and Basu-Ranwu-Bomi area,only a few of them are distributed in Changdu area,mainly in alpine valley area,and very few in northern Bangda grassland area.From the point of view of micro-topographic characteristics,it mainly occurs on concave slopes and low-lying areas along the direction of slopes,which provides accumulation space for the formation of granular slopes.(3)According to the characteristics of lithology and spatial distribution of disasters,the hazards of granulites along G318 National Highway can be divided into four sections by using the method of fuzzy comprehensive evaluation.Area I(Changdu area)belongs to the high mountain and gorge area in eastern Tibet.There is a granular slope developed in this investigation area.The hazard is judged to be small,and the impact on the G318 national highway is relatively small.Area II(Bangda area)belongs to the eastern Tibet Alpine Canyon Region in geomorphology.Under the influence of elevation,slope and climate wind direction,three granular slopes have been developed in the investigation area.The hazard ismoderate,and the influence is small along the line.The third area(Basu area)belongs to the high mountain and gorge area in eastern Tibet.There are six granular slopes in this area,which have great danger and great influence on the tunnels along the railway,and should be properly handled.Area IV(Ranwu and Bomi)This area belongs to the eastern Tibet Alpine canyon area in geomorphology.There are six clastic slopes in this area,which are dangerous and have great influence on the area along the line.