Study On Formation Mechanism And Stability Of Nizheng Landslide In Batang Hydropower Station

Over the past half century,there have been many landslides in the world,and brought huge losses to mankind.In order to avoid the occurrence of such events,it is the key to solve the problem,and it has been paid close attention to the academic and engineering circles in order to avoid the occurrence of such events.In recent years,there are many studies on the landslide in the reservoir area,but there are relatively few studies on the landslide with weak base,especially the lithology of the overlying slope is the massive intrusive rock.In this paper,the Nizheng landslide is located in the weak base slope,the hard rock belongs to the massive structure of the quartz diorite,the front of the landslide is thin,medium to thick layer of mica quartz schist,while the landslide is located in Sanjiang deep It is of theoretical significance to study the landslide with similar structure.It can be used as a reference for the study of the landslide with similar structure.The Nizheng landslide is located within the reservoir area of the proposed Baotang hydropower station.The shear outlet of the landslide is located below the normal water level of the reservoir.The water storage is bound to affect the stability of the landslide and affect the life and property of nearly 100 residents on the slope,So it is of practical significance to predict the stability of the landslide after the impoundment is the key to the normal operation of the hydropower station.In this paper,the Nizheng landslide is used as the research object.The engineering geological conditions of the landslide area are described in detail.Then the morphological scale,boundary feature,material composition and deformation and failure characteristics of the landslide are analyzed in detail.Then,based on the geological conditions and basic characteristics of landslide,the formation conditions of landslide are analyzed.On this basis,the formation mechanism of landslide is studied by geological analysis,physical simulation and discrete element simulation.Finally,the stability of the landslide before and after the impoundment is calculated by two-dimensional and three-dimensional numerical simulation,and the collapse of the landslide and its influence on the stability of the landslide are predicted.The main research results are as follows:(1)The study shows that the active geological period,the steep terrain,the complex geological structure and the double-layer structure of the slope constitute the basic conditions for the formation of the landslide.The geological environment of rainfall and high intensity is the main external factor to induce the landslide.Combined with the basic characteristics of the landslide,the formation process of the landslide is divided into three main stages: the initial deformation stage,the cumulative deformation stage and the landslide.The main deformation and failure modes are dumping deformation and slip compression cracking.(2)The deformation and failure process of the landslide under gravity is reproduced by the physical simulation of the bottom friction.The simulation results show that the first layer is the anti-dip layered quartz rock of the front of the slope,which provides the basis for the deformation of the middle and rear slope.The whole physical simulation shows the development of the sliding surface from the bottom edge of the front edge and the trailing edge of the trailing edge from the top to the bottom,and finally forms the potential slip surface with the locking section.(3)The influence of rainfall and earthquake on the formation of landslide is studied by using discrete element numerical simulation.The results show that both of them can aggravate the landslide deformation,resulting in a large-scale slip of the landslide,but the seismic landslide has a continuous Time is shorter,the occurrence of larger,more distant movement characteristics.(4)The results show that the stability of the landslide is good,but the stability of the leading edge is obviously weakened,which is the underdevelopment state.The results show that the stability of the landslide is better than that of the landslide.The results show that the collapse area does not have a direct impact on the population concentration area on the slope,but it is confirmed that the bank collapse will adversely affect the stability of the landslide,leading to the stability of the leading edge Further weakened,but the overall stability of the change is not obvious,the stability of the state is still good.The stability of the landslide is analyzed by three-dimensional calculation,and the same conclusion is obtained as the two-dimensional calculation,that is,the leading area is the main influence zone after impoundment.