地震载荷作用下混凝土重力坝损伤分析

Damage analysis of concrete gravity dam under earthquake load

为了深入研究混凝土重力坝在地震载荷作用下进入非线性状态并发生损伤破坏的力学机理,通过损伤力学理论对混凝土重力坝的损伤机制进行分析,运用有限元软件对混凝土重力坝发生损伤现象进行数值模拟。分析在x、y方向的地震载荷作用下,混凝土重力坝发生损伤的区域。监测坝体靠近损伤区域的节点的主应力变化情况。研究表明:在坝踵、坝趾以及坝颈下游面这些应力集中区域易发生损伤现象,主应力随着地震加速度时程变化而变化,地震加速度幅度越大,坝体的受拉应力水平越高,范围也越大,拉应力水平极易达到抗拉强度,进而发生损伤现象。揭示了混凝土重力坝在地震载荷作用下损伤的发生机制,为混凝土重力坝的设计和施工提供理论依据。

In order to deeply research the mechanics theory of concrete gravity dam into the nonlinear state and the damage failure under the earthquake force, the article analyzed the damage failure mechanics of the concrete gravity dam and the damage region under earthquake load ofx ,y direction, numerically simulated the damage phenomena by finite element software, and monitored changes of principal stress of the nodes which were near the damage region. The results show that it is easy to occur damage phenomena at stress concentration regions, such as dam heel, dam toe and dam cervical downstream. The principal stress has changed with the changes of earthquake acceleration time histories, the larger the amplitude of earthquake acceleration, the higher the level of tensile stress. It is easy to reach the tensile strength, then occur the damage phenomena. The damage mechanism of the concrete gravity dam under the earth-quake load was revealed, witch can provide theoretical basis for design and construction of concrete gravity dam.