考虑强震持续时间的混凝土重力坝损伤累积研究

利用混凝土塑性损伤模型和塑性损伤力学的方法分析了混凝土重力坝在不同强震持续时间(强震持时)作用下的非线性损伤累积破坏效应,并根据大坝局部损伤评价指标和整体损伤评价指标对大坝损伤累积破坏程度进行了评价。分析结果表明:地震动强震持续时间对混凝土大坝损伤累积破坏有重要的影响,地震动强震持续时间越长,混凝土大坝损伤累积破坏越大;根据局部损伤评价指标可以有效地判定大坝抗震薄弱部位在大坝中上部,并且大坝整体损伤累积破坏指数可以反映地震动作用下大坝的整体损伤累积破坏程度,从而有效评价混凝土大坝的抗震性能,为混凝土大坝的抗震设计提供科学依据。

Study on accumulated damage of concrete gravity dam under consideration of strong-motion duration

The nonlinear accumulated damage effects of concrete gravity dam under the impacts of various strong-motion durations are analyzed herein with the plastic damage model and the plastic damage mechanics method for concrete，meanwhile，the degree of the accumulated damge of the concrete dam is evaluated in accordance with the relevant local damage assessment index and the integral damage assessment index for the dam as well. The analysis result shows that the strong ground motion duration has an important impact on the accumulated damage of the conrete，i.e. the longer the duration is，and the larger the damage is to be. According to the local damage assessment index，it can be effectively determined that the weak zone of earthquake resistance is located at the middle to upper part of the dam，furthermore，the degree of the integral accumulated damage of the dam under the impact of the ground motion duration can be reflected by the integral accumulated damage index of the dam，thus the seismic performance of the concrete dam can be effectively evaluated for providing a scientific basis for the seismic design of it.