混凝土坝地震动力损伤分析_杜成斌.pdf

第20 卷第5 期 工 程 力 学 Vol. 20 No.5 2003 年 10 月 ENGINEERING MECHANICS Oct. 2003 文章编号：1000-4750(2003)05-0170-04 混凝土坝地震动力损伤分析 杜成斌，苏擎柱 (河海大学土木工程学院，南京 210098) 摘 要：基于塑性损伤本构理论，将损伤变量作为内变量，在 Drucker-Prager 本构模型中引入损伤变量，考 虑材料损伤引起的材料劲度的退化，基于非关联流动法则计算材料的塑性应变，根据材料的有效塑性应变 计算损伤量，考虑到张开裂缝闭合时材料弹性劲度的恢复，推导了考虑塑性损伤的混凝土动态本构关系， 并给出了内变量的计算步骤和动力方程的迭代格式。最后利用建立的动态本构模型对Koyna 重力坝进行了 非线性地震响应时程分析，并给出了关键时刻坝体最大受拉损伤分布，结果表明在坝颈和坝基处出现了较 大的损伤，坝颈处的损伤最终形成由下游向上游的开裂破坏，这与该坝的实际震害较为一致。 关键词：塑性损伤；混凝土重力坝；本构模型；非线性；地震分析 中图分类号：TV642.3, TV312 文献标识码：A DYNAMIC DAMAGE OF CONCRETE GRAVITY DAMS UNDER EARTHQUAKE EXCITATION DU Cheng-bin , SU Qing-zhu (College of Civil and Engineering, Hohai University, Nanjing 210098, China) Abstract: A new plastic-damage constitutive model for cyclic loading of concrete has been developed for the seismic analysis of concrete dams based on plastic-damage theory. Damage variable is used as an internal variable, which is included in the Drucker-Prager yield function. Stiffness degradation induced by material damage is considered in the model. The plastic strain rate is obtained according to the nonassociative flow rule. Damage evolution is determined by effective plastic strain. The crack opening/closing behavior is modeled as elastic stiffness recovery during elastic unloading from a tensile state to a compressive state. The main steps of the algorithm for the internal variable and nonlinear dynamic equation are presented in the paper. The plastic-damage model is used to evaluate the response of