Numerical Simulation Of Foundation Excavation And Geological Body Deformation Response On The Left Bank Of A Hydropower Station

It is one of the world’s tallest high arch dams.The dam area of the hydropower.The hydropower station in the study area is 305m high and has an installed capacity of 3,600MW.It is one of the world’s tallest high arch dams.The dam area of the hydropower station has high slopes on both banks and the geological environment is complex.The shallow and deep geological effects on the left bank are strong.Under the conditions of large excavations on the left bank,a complex,large-scale high-steep engineering slope is formed.The stability of the slope of the spandrel groove in the project area greatly affects the safety of the buildings in this area.This paper takes the excavation slope of the spandrel groove on the left bank as the research object,and obtains a more detailed understanding of the geological environmental conditions of the engineering area,the boundary of the excavated slope,and the structural characteristics of the slope rock mass by consulting relevant data.On this basis,FLAC3D numerical simulation is used to explore the internal relationship between slope deformation and different excavation angles.The specific research content and results are as follows;(1)Through on-site investigation,consulting relevant materials,and combining with previous research results,the rock structure characteristics of the left bank spandrel groove slope,including structural structural planes(such as faults,rock veins),shallow surface and deep structures Research on the surface(weathered unloading zone,etc.),and establish a generalized model of the slope geology.(2)Based on the deformation and failure phenomena exposed during the excavation of the left bank slope in the study area,combined with the deformation monitoring data of the left bank slope and the characteristics of the rock mass structure,analyze the deformation and failure modes and mechanisms of the left bank.The results show that the signs of deformation during the excavation of the side slope of the left bank spandrel groove belong to the excavation unloading deformation of the superficial layer.(3)Using numerical simulation analysis methods,three types of slope FLAC3D models with different excavation angles are established,and the displacement characteristics,principal stress conditions and maximum shear strain increment characteristics of the slope at each excavation angle are analyzed for comparison and analysis.Compared with 63° and 53°,the slope after excavation at an angle of 58° has better stability and no local instability.At the same time,considering the engineering quantity and other factors,the 58° excavation is determined to be the best Appropriate solution.(4)A comprehensive comparison of the slope conditions at the three excavation angles shows that the slope after excavation at an angle of 58° has a small amount of unloading rebound and good slope stability;the slope after excavation at 63° Slope,with higher steepness,greater displacement of the slope surface to the empty direction,more obvious stress concentration,and greater excavation;on the slope after 53° excavation,lamprophyre vein X exposure It is not optimistic.After the excavation of the slope,due to the existence of lamprophyre veins,local displacements exceeding 1.1 cm occur,and the slopes are more likely to collapse and fall locally.Considering comprehensively,among the three excavation methods,the first one(58°)is the most ideal one.