| Through long-term internal and external dynamic geology,the strata in the study area are subject to multiple geological tectonic deformation and transformation,the multiple superimposed folds and regional faults are formed.And it controls the basic trend of the main ridges and valleys in Gongjue area.The Jinsha River basin shows strong river erosion since entering the geological tectonic period of the Himalayas.Therefore,the mountain canyon landform was formed in the study area.The complicated landform and geological structure have resulted in numerous geological disasters mainly caused by landslides in the study area.The landslides in the study area are mainly small-sized or large-sized and they occur frequently.In recent years,the local government has been increasing its investment in Gongjue county and the scope of human engineering activities has gradually widened.Landslides and other geological disasters pose a great threat to the safety of life and property of local residents.Thus,we should fully investigate the geological background and landslides in Gongjue and find out their development characteristics,distribution rules and environmental conditions for forming major geological disasters.In addition,we should analyze the controlling factors of landslides.It can not only timely and effectively protect people's life and property safety in Gongjue area,but also reduce casualties and property losses caused by geological disasters and maintain social harmony and stability.On the basis of field investigation and related data collected by predecessors,I studied the spatial distribution characteristics and controlling factors such as slope,lithology,rainfall in the study area were systematically sorted out and analyzed.There are mainly following aspects of understanding:First,the Jinsha River fault zone controls the topography along the route and create the high mountain and canyon areas we see so far.The slope on both sides of the river valley is large,the unloading effect occurs and the effective frontage surface is developed.In addition,the joints and fissures are extremely developed,and the cracks increase with the continuous rise of the terrain.What`s more,the groundwater and rainfall infiltrate into the slope body through the joints and fissures,resulting in the softening of the rock and soil mass.And it makes the hydrostatic pressure increased.Finally,most of the landslides are concentrated in the Jinsha River valley.Second,there is a great correlation between the terrain elevation fluctuation with the change of the terrain slope in the study area.That is,the terrain slope corresponding to the area with large elevation fluctuation is large,and the landslides distribution is concentrated.The 10°?50° attribute section has a great sensitivity to landslides.Third,based on the statistics of the project,I obtain the type of material composition of the sliding body.It is found that the variation of landslides ratio between different formation lithology is small,which indicates that the formation lithology is not the main controlling factor of landslides in study area.Fourth,in July,when the number of landslides in the study area was the highest,the frequency of heavy rain was the highest.It shows great consistency between the number of landslides and the frequency of heavy rain.At the same time,the concentrated distribution of landslides is proportional to the rainfall,which fully indicates that rainfall is an important trigger factor of landslides in this region. |
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