Stability Analysis Of Dynamic Response Of High Core Wall Earth And Rock Dam And Its Grid Reinforcement

To give full play to the role of dams in flood control,water storage,water supply,and power generation,the construction of high dams and ultra-high dams has become a key project in the comprehensive utilization and development of water resources at home and abroad,and earth and rock dams are widely built for their many advantages.When high earth and rock dams are subjected to strong earthquakes,the "whip effect" starts from the dam’s top area.Therefore,when building high earth and rock dams in areas of high seismic intensity,the necessary measures should be taken to strengthen the dam body for seismic stability.Geogrid,with its advantages of high strength and low deformation,is used as a new reinforcement material for the seismic stability reinforcement of dams,and a reasonable arrangement can effectively bring into play and improve the strength and self-stability of the fill body.In this paper,a finite difference procedure is used to simulate and study the reinforcement stability of high earth and rock dams,which is expected to provide some reference value for the design and reinforcement of earth and rock dams.The study is based on a 295 m high core wall earth-fill dam.The Lagrangian finite difference method is used to simulate the stress and strain of the dam body and the effect of geogrid reinforcement under the earthquake,to determine the best way to lay the geogrid reinforcement and to analyze the seismic stability of the earth-fill dam in terms of slope stability and permanent deformation after the earthquake.The main elements of the thesis research are as follows:(1)Reinforcement of the dam body above 4/5 height,and determination of the optimal parameters of geogrid reinforcement material by analyzing the permanent displacement deformation of a geogrid-reinforced high earth and rock dam under the influence of strong seismic loads.The calculation results show that the top of the dam is reinforced with the grating,the axial displacement of the top of the dam,the vertical displacement,and the horizontal displacement of the dam are reduced,and the reinforcement effect is obvious.The effect of different moduli of elasticity,laying length,and layer spacing on the reinforcement effect is compared and analyzed.It is recommended that the modulus of elasticity of the grating be 2.5 GPa,the length of the grating be in the form of full laying,and the spacing of the grating be 4 meters.(2)The core wall earth and rock dam studied were reinforced with the best grating parameters analyzed.The maximum principal stress,the minimum principal stress,and the shear stress of the dam body changed after reinforcement.The initial state produced compressive stresses on the slope of the dam body due to consolidation settlement,and the compressive stresses became tensile stresses under seismic action,and the principal stresses were reduced after reinforcement by laying grids.The maximum shear stress occurs at the junction of different partition materials,and the shear stress increases the underground shaking load,the stress distribution changes after grating reinforcement,and the maximum shear stress decreases.(3)By loading horizontal unidirectional seismic waves and loading horizontal seismic waves and vertical seismic waves at the same time,the stress-strain,permanent displacement change,and seismic acceleration of the dam body with the height of the dam were compared and analyzed,and it was found that the vertical ground shaking had less effect on the permanent displacement of the dam body,and the damage was mainly caused by horizontal ground shaking.(4)Under the influence of ground shaking load,the upstream slope of the earth and rock dam has less displacement change compared to the downstream due to the water pressure.When reinforcing the dam’s stability,more attention should be paid to the protection of the downstream slope compared to the upstream waterfront.