Study on seismic wave propagation regularity and dam-foundation interaction characteristics of earth-rock dam on deep overburden

Abstract

Many dams have to be constructed on deep overburden in meizoseismal areas, so it is vital to understand the seismic performance of these dams. Current research primarily focuses on the whole seismic response of dams, in which the analysis can be relatively imprecise. Nevertheless, an in-depth understanding of the propagation regularity of seismic waves in earth-rock dams on deep overburden, as well as the interaction characteristics between the dam and overburden, is critical. In this paper, based on a planning soil core wall dam with over 500 m of overburden, the seismic wave input method is employed to conduct a detailed and in-depth study from the perspectives of the spatial distribution of seismic acceleration and the Fourier spectra of acceleration time history. The results indicate that the spatial distribution of the peak acceleration of the dam is significantly inconsistent. The horizontal peak acceleration of the upstream side of the dam is greater than that of the downstream side because the dynamic modulus of the dam is significantly inconsistently distributed. In addition, the amplification behaviours of the seismic wave are different in the overburden and dam body, and the low-frequency and high-frequency components are amplified. The dynamic interaction between the dam body and the overburden significantly reduces the acceleration response at the dam-foundation interface by 44 % and 50 % in horizontal and vertical accelerations, respectively, because of the absorption of seismic wave energy by the dam body and the inconsistency of the dynamic modulus distribution of the overburden. The findings of this study provide robust theoretical support for evaluating the seismic performance and designing measures for the seismic resistance of earth-rock dams on deep overburden.