Deformation Characteristics And Stability Analysis Of A Landslide In Tangjiashan Dammed Lake

Reservoir landslides have always been the focus of landslide research.In the existing studies,most of them use 2D models or false 3D models formed by longitudinal stretching of a section of the landslide as the object of analysis,and research on true 3D models identical to actual terrain is less.Moreover,there are relatively few studies on landslides in dammed lakes.The water level changes rapidly after the formation of the dammed lakes.Few scholars have studied the regularity between the speed of dammed lake water level change and the deformation characteristics and stability of the landslide body.In this paper,a landslide body in Tangjiashan dammed lake is selected as the research object.First,the engineering geological conditions of the landslide are analyzed by collecting data.Then,based on the survey data,a true 3D model identical to the actual terrain is established.The FLAC3 D numerical simulation method simulates the state of the landslide under natural conditions,rapid rise in water level at different speeds,and rapid decline in water level at different speeds,obtains the deformation characteristics of the landslide body in different states,and analyzes the stability change law.Finally,due to the high probability of earthquakes in the area,an earthquake action is applied to the slope to predict the state of the landslide body under earthquakes with different peak accelerations.The main conclusions of this article are as follows:(1)After data collection and research on the engineering geological conditions of the landslide,it was found that the landslide is a medium-sized shallow landslide.Affected by the elevation of the Tangjiashan dammed Lake,the steeper terrain in the lower left part of the landslide has deformed,and several cracks have appeared in the middle part of the left side.The stability has changed.(2)Through the analysis,it is found that the landslide is in a stable state in the natural state,with small deformation,but less safety reserves.At the same time,the deformation characteristics and stability changes of the slope with different water level rise and fall speed are obtained.When the water level rises,if the speed is fixed,the stability of the landslide mass will gradually increase with the rise of the water level,and the increment of displacement and maximum shear strain will be small,and the change will not be big;if the elevation of the water level rise is fixed,the stability of the landslide mass will be slightly increased with the increase of the water level rise speed,and the increment of displacement and maximum shear strain will be small,and the change will not be big.When the water level drops,if the speed is certain,the stability of the landslide body will gradually decrease with the drop of the water level,and the displacement and the maximum shear strain increment will gradually increase;if the water level drops at a certain elevation,the stability of the landslide body will gradually decrease with the increase of the water level drop speed,and the displacement and the maximum shear strain increment will also gradually increase.It can provide some reference for landslide control.(3)The effects of earthquakes with different peak accelerations on the landslide body are predicted,and the analysis of the two sets of monitoring points shows that the seismic acceleration has an amplification effect,and the effect is related to the monitoring point elevation.