Seismic Response Of Earth-Rockfill Dam On The Overburden

Earth-rockfill dam is widely used because of its simple and convenient, can well satisfy various geological conditions. As geological condition restriction, more and more earth-rock fill dams are built in strong earthquake and deep overburden area. There are lots of technical problems when the earth-rockfill dam are built on deep overburden, especially seismic performance is attracted the attention widely, so it is meaningful to study on seismic performance of the earth-rockfill dam.This paper takes the earth-rockfill dam on the deep overburden and highly seismic region as background, and applies equivalent viscoelasticity model to analyze two-dimensional dynamic response of earth-rockfill dam under different layer thickness and different dam higher working conditions. The work of this paper is as follows:(1) This paper calculates and analyzes effect of overburden whether exited and different thick of overburden to seismic response of homogenous rockfill dam which is 40 meters and 80 meters high. It includes research on the dynamic response of the law, comparing the dynamic distribution coefficient with the criterion and discussing the applicability of the dynamic response of the dam on deep overburden. The results show that the criterion is suit for the dam on the rock, but it isn't appropriate to use the criterion when analyzing the stability of the dam on deep overburden, need to use the finite element method.(2) This paper also calculates and analyzes seismic response of asphalt concrete core wall dam which is 50 meters,100 meters,150 meters and 200 meters high, with the overburden which is 40 meters,80 meters,120 meters,160 meters and 200 meters thick. It includes research on seismic response of the dam with different thick of overburden and different earthquake waves, effects of vertical seismic, sensitivity analysis of dynamic responses K value of overburden. The results show that acceleration amplification of dam on the deep overburden is relevant to ground motion input. The thicker the overburden is, the smaller the acceleration amplification. But because of overburden change of seismic wave spectrum characteristics, dam dynamic response of the law will change. Along with the increase of ground motion input values and thickness of overburden, dynamic horizontal displacement increases. Along with the increase of K value of overburden, acceleration amplification of dam increase. In different under the action of dam seismic, seismic response difference is bigger.(3) This paper also calculates and analyzes effect of different boundary conditions to seismic response of homogenous rockfill dam which is 100 meters high, with the overburden which is 50 meters,100 meters,150 meters and 200 meters thick. The results show that the calculation results between the visco-elastic edge and rigid boundary have large difference, and calculation results of visco-elastic boundary is smaller. It is explain that radiation damping has great influence on dam reaction, in order to consider the influence of radiation damping, try to improve boundary conditions and calculation method.