摘要
拱坝坝体中缝界面在地震作用下的开、合模拟对拱坝地震反应有重要影响。目前在拱坝地震反应分析中应用的一些模型，如Fenves模型、Dowling的三参数模型，存在对缝界面的接触状态模拟精度不高的问题，这对于准确评价工程上关心的经界面最大张开度是不足的。此外，坝基中存在的断层、节理、裂隙等软弱夹层的非线性力学特性和无限地基能量辐射作用对拱坝地震反应也有重要影响．在拱坝地震反应分析中同时考虑这三种影响因素难度很大，在国际上尚未解决，本文将动接触力模型与景式有限元的波动模拟方法相结合，解决了这一难题，并且提高了缝界面接触状态的模拟精度．文中还利用动力学方法求解了拱坝的静态反应，并在此基础上提出了上种适用于非线性结构反应的静、动作用组合方法。最后；以拟建中的小湾拱坝为例分析了横缝和底缝对拱坝地震反应的影响。
It is important for the seisndc response analysis of arch dams to simulate opening and dosing of cracks in the dam under strong earthquake. The present models used in seismic response analysis of arch darns, such as Fenves' model and Dowlings' model, have the shortcodring that the accuracy to simulate the contact state between cracked surfaces is not high.It results in that the maximum opetting between cracked surfaces is not predicted accurately. In addition, the nonlinear behaviors of geological structure 'are unavoidably existing in the near-field foundation for every dam site and the effects of the energy dispersion in the infinite foundation are also important for the seisAnc response analysis of arch dams. It is diffcult to con gider the three factors mentioned above together in the seismic response analysis of arch dams, and it has not been solved yet. Combining a contact force model simulating the contact condition between the contact interfaces with an explicit finite element method in which the artificial boundary condition is a transmitting boundary is used to solve this diffcult problem and the contact force model has better accuracy for the contact state simulation between the cracked surfaces than Fenves' model, which is verified by comparing the results calculated by the contact foree model and Fenves' model with the results tested on shaking table. In this paper, the static response of arch dams is solved by using the dynaAnc analysis method, and furthermore, a combining method for the action of static and dynamic load is proposed for the nonlinear response of arch dams. Finally. Some results are obtained by using this approach to the seismic analysis of a designed Xiaowan arch dam with contracted joints and bottom crack on the dam with maximum height of 292m in China.
出处
《地震工程与工程振动》
CSCD
北大核心
2000年第1期11-20,共10页
Earthquake Engineering and Engineering Dynamics
基金
国家"九五"重点科技攻关项目!96-221-03-02-02
国家自然科学基金!59739180
关键词
拱坝
缝界面
无限地基
地震反应
地震波
arch dams, cracked surface, infinite foundation, seismic response
