大岗山高拱坝强地震作用下损伤破坏分析

采用连续损伤力学中能量等效原理和有效应力概念,将混凝土强度降低、刚度劣化即损伤作为不可逆内变量张量,并考虑应变率效应和多轴应力状态,建立率相关弹塑性损伤模型.应力本构积分采用返回映射法,给出了有限元程序主要功能流程.对强地震作用下大岗山高拱坝损伤和破坏情况进行数值模拟,评价其强震后的安全性.结果显示,大坝在强震后总体损伤不大,结构安全性较好,但应注意抗震薄弱部位;同时大坝不同部位率响应明显不同,对混凝土力学性能影响不容忽视.

Damage and fracture analysis of Dagangshan arch dam under strong earthquake

The theory of energy equivalence and effective stress concept are applied to analyze damage and fracture for Dagangshan high arch dam (210m) and its safety to resist strong earthquake. Damage is considered as irreversiblly internal variable to deal with strength reduce and stiffness degradation for concrete under loading. Damage tensor including characteristic of rate-dependent of concrete and effect of multiaxial stress for structures is used to set up rate-dependent elasto-plastic damage model. Return mapping algorithm is selected to solve stress integral in constitutive equation. Main procedure for finite element program is presented. The dam is simulated numerically to analyze its damage and fracture and is evaluated from the view of safety to resist strong earthquake with peak earthquake acceleration of 0.5575g. The results show that the dam's damage is in low grade and is good in integer after strong earthquake. But some zones of the dam are weak to resist earthquake such as the joint of dam and foundation at the bottom and the top arch of the dam. Meanwhile, strain-rate response is different for each zone of the dam and should not be neglected to strength and deform of concrete.