南水北调与水利科技（中英文）2025，Vol.23Issue(4)：1015-1024,10.DOI:10.13476/j.cnki.nsbdqk.2025.0102
基于地表设计地震动的成层地基-混凝土重力坝系统损伤特性
Damage characteristics of layered foundation-concrete gravity dam system based on surface design ground motion
摘要
Abstract
As a widely used hydraulic structure in water conservation projects,the seismic fortification of concrete gravity dams has garnered significant research attention.However,traditional seismic analysis methods often simplify the foundation as a single-line elastomer.While this approach simplifies calculations,it also overlooks the layered inhomogeneity of the natural site.Due to the layered non-uniformity of natural foundations,the impedance ratios between different rock layers vary,making the traditional method of halving the design ground motion at the surface for a single-layer foundation insufficient. The ground motion is designed based on the landmark criteria,taking into account the transmission and reflection effects of seismic waves between layered foundations.According to the propagation law of seismic waves in both horizontal and vertical directions,the seismic waves in both directions are jointly inverted.The free field motion at any position of layered foundation is solved by transfer matrix method.By combining viscoelastic boundary and equivalent nodal force,an inversion-input model of layered foundation based on surface design ground motion is established.Using this model,the nonlinear seismic response analysis of an actual concrete gravity dam is carried out.The influence of layered foundation on the seismic response of gravity dam is analyzed from three aspects:relative displacement of dam crest,damage distribution within the dam body and energy dissipation due to damage in the dam body. The results show that:(1)The layered characteristics of the foundation significantly impact the relative displacement of the dam crest.Compared to the layered foundation,the relative displacement of the single-layer foundation is 34.6％,87.6％,and 87.6％,respectively.Vertical relative displacement increases were 8.0％,33.6％,and 97.1％,respectively.Generally,the relative displacement at the crest is larger for the single-layer foundation than for the layered foundation.(2)The layered characteristics of the foundation also significantly affect the damage of the gravity dam.Foundations with smaller elastic modulus experience more severe damage.Damage distribution of the dam under the single-layer foundation is generally greater than under the layered foundation.In the layered foundation,there is slight damage and cracking at the upper and lower reaches of the slope,and the damage distribution area is small.Compared with the layered foundation,the cracks at the upstream slope of the single-layer foundation extend downstream,and the crack length and damage area at the downstream slope increase.(3)Considering the layered foundation,the dam's damage dissipation energy is small.Compared to the layered foundation,the damage dissipation energy of model 2 is reduced by about 10％,whereas the damage dissipation energies of models 3 and 4 increase by 6.5 times and 3.3 times,respectively.The damage dissipation energy of the dam is greatly influenced by the material parameters near the surface;the closer these parameters are,the more similar the damage dissipation energy becomes. Therefore,in the study of ground motion input,the layered heterogeneity of the site should be considered.Ignoring the layered characteristics of the foundation may lead to an overestimation of the dam's response results.关键词
成层地基/混凝土重力坝/反演输入/黏弹性人工边界/损伤特性Key words
layer foundation/concrete gravity dam/inversion input/viscous-elastic artificial boundary/damage characteristics分类
建筑与水利引用本文复制引用
李志龙,刘云贺,刘托弟,李闯,宋志强..基于地表设计地震动的成层地基-混凝土重力坝系统损伤特性[J].南水北调与水利科技（中英文）,2025,23(4):1015-1024,10.基金项目
国家自然科学基金重点项目(52439008) （52439008）
陕西省教育厅青年创新团队科研计划项目(22JP052) （22JP052）
