非一致地震作用下高坝－复杂地基体系动力响应分析

The construction and input of seismic wave fields are the key factors in the seismic analysis of high dam structures. This paper proposes a time-domain method for solving the free wave field under a three-dimensional layered foundation. A remote layering interface model is established to separate the upgoing and downgoing wave fields, which can solve the construction of wave fields in complex geological structures such as irregular sites. Combined with the continuity and vibration characteristics of different wave patterns, the single column node displacements are extended to the whole site by geometric derivation to improve the solving efficiency. An improved wave input method is used to convert the complex wave field into the equivalent nodal force on the foundation boundaries. The response of the 3D high dam-foundation system under vertical and oblique incident SV waves is studied, and the results are compared with those of homogeneous foundations; all the examples are completed on the supercomputer center platform. The results show that the dynamic response of the dam under non-uniform seismic waves has a significant spatial difference, and the maximum displacement response at different locations of the dam crest can vary by up to 80%. When the SV wave is obliquely incident, the vibration response of the dam is much larger than that of the vertical incidence; the extreme displacement value can be different by 2 -3 times, and the time period of high stress area is different greatly, and the scope of tensile cracking of system is wider. Complex geological conditions will aggravate the dam' s damage and significantly influence the distribution of high-stress regions. This paper proves that it is necessary to consider the non-uniform characteristics of seismic waves and the geological structure of the site, which can provide a reference for the seismic response analysis.