摘要
将损伤、渗流及孔隙率演化等相互耦合的有效应力概念引入Mohr-Coulomb破坏准则,对岩石类的脆性材料建立了一种动力损伤破坏的模型,并应用该模型对地震荷载作用下的坝和岩基的破坏过程进行了脆性动力损伤分析。这种方法从连续损伤力学的观点研究了岩体结构在动力荷载作用下脆性损伤-破坏的突变机理。结果表明,损伤会在坝与岩基的上游坡的结合处由于应力集中而明显地增长。在硬岩基上的坝内,损伤发展比软岩基上灵敏。
In this paper,a brittle damage-failure mechanism for rock structures subject to earthquake loading is adopted for analysis of dynamic responses of damaged concrete gravity dams and rock foundation. The concept of the modified net effective stress which involves the coupling affects among damage,pore pressure and porosity evolution in cracked rock mass and concrete is introduced into the modified Mohr-Coulomb failure criterion in order to express the brittle dynamic damage growth and propagation phenomenon. The developed brittle dynamic damage model is based on the localization of damaged failure in brittle materials. Therefore,the brittle dynamic damage process is considered as the process of local fractures in material without plastic deformations. The dissipations of energy during the dynamic process consist of dissipations of the local damage development,the local changes of seepage flow velocity and the local evolution of porosity within the networks of crack-damaged porosity only; no energy is dissipated with the everlasting deformation. The numerical results of the brittle dynamic damage analysis for the concrete dam and the rock foundation show that the significant damage growth starts in the upstream side at the corner between the dam and rock foundation where a high stress concentration area exists. Damage growth is found to be more susceptible in the softer rock foundation than that in the intact rock foundation.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2004年第8期1311-1317,共7页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金(50379046)资助项目
关键词
坝基
岩石力学
地震荷载
脆性损伤突变
地震响应
rock mechanics,localization of brittle fracture-damage,damage evolution,dynamic finite element analysis,dam and rock foundation,earthquake response
