近断层地震动作用下重力坝损伤特性研究

Research on Damage Characteristics of Gravity Dam under Near-fault Ground Motion

为了解近断层脉冲型地震动作用下的重力坝损伤特性,以Koyna重力坝为例建立了塑性损伤模型,并对模型的正确性进行了验证。从坝体损伤区域分布、坝顶关键点位移以及坝体损伤耗能情况3个方面出发,对比研究了具有向前方向性效应、滑冲效应和无脉冲效应近断层地震动对重力坝损伤特性的影响。结果表明:向前方向性效应地震动作用下坝体产生的损伤破坏范围、坝顶关键点位移变形及坝体损伤耗能最大,其次为无脉冲效应地震动,滑冲效应地震动造成的影响最小,说明向前方向性效应地震动会对重力坝产生更为严重的损伤破坏影响,在重力坝抗震设计过程中应重点关注向前方向性效应地震动造成的影响。

In order to understand the damage characteristics of gravity dams under the action of near-fault pulse-type ground motions,a plastic damage model is established by taking the Koyna Gravity Dam as an example,and the correctness of the model is verified.The damage characteristics of gravity dams caused by near-fault ground motions with forward directional effect,slip effect and non-pulse effect are comparatively studied from three aspects of the distribution of damage area of dam body,the displacement of key points of dam crest and the energy consumption of dam body damage.The results show that the damage and damage range of dam body,the displacement and deformation of key points of dam crest and the damage energy consumption of dam body under the action of forward directional effect ground motion are the largest,followed by the ground motion without pulse effect,and the impact caused by sliding effect ground motion is smallest.It shows that the forward directional effect ground motion will have a more serious damage and damage impact on gravity dam,so the impact of forward directional effect ground motion should be paid attention to in the seismic design of gravity dam.