Study On Stability Evaluation And Control Methods Of Lengganliang Landslide In Wudu District Of Longnan City

Wudu District of Longnan City is located in the southeast of Gansu Province and is the intersection of the Qinba Mountains,the Loess Plateau,and the Qinghai-Tibet Plateau.It forms a complex terrain with high mountains and valleys and valley basins.Therefore,this place is one of the most developed geological disasters in Gansu Province.Its favorable geological conditions and extreme weather conditions have contributed to the formation and occurrence of landslides.This paper takes the Ruganliang landslide in Wudu District of Longnan City as the research object,and studies the basic characteristics,forming factors and stability of the landslide,and considers it based on the analysis of the Lengganliang landslide and the Dujiagou debris flow ditch where it is located.The unified design proposes a comprehensive disaster management plan.The main research results are as follows:(1)Through the field survey of landslides,the basic characteristics of landslides are obtained,and the material structure characteristics and degeneration characteristics of landslide bodies and landslide soils are analyzed,and the formation conditions and causes of landslides are discussed.The Lengganliang landslide is formed by the resurrection of the old landslide.The sliding surfaces of the landslides H1 and H1-1 are polygonal and the sliding surface of the H1-2 is an arc.(2)The formation of this landslide,in addition to the poor material composition of the landslide,unstable physical and mechanical properties,steep terrain and other basic conditions,the earthquake and human activities are the main influencing factors.(3)Using the limit equilibrium method and the Swedish score method to evaluate the stability of the Lengganliang landslide and its developed secondary landslides,we know that the landslide H1 is in an understable condition and the landslide H1-1,H1-2 is also in an under-stable state;in the deadweight and storm conditions,all three landslides are in an unstable state;under the self-weight and earthquake conditions,the three landslides are also in an unstable state.(4)According to the related characteristics of the Lengganliang landslide,combined with the disaster development of the Dujiagou debris flow ditch,a comprehensive treatment plan of “blocking,expulsion and anti-sliding support” was proposed.