两种动水压力模型重力坝地震动力损伤比较分析

采用基于位移格式的流体单元与弹塑性损伤本构的固体单元分析了坝体—水库耦合系统在强震下库水对重力坝的动力响应、坝体内部应力分布以及损伤的影响。对流固耦合模型与附加质量模型的坝体损伤分析结果进行比较发现,附加质量模型不仅对上游坝面的动水压力有放大作用,而且对坝体的其他动力响应,如位移、加速度,也有不同程度的放大作用。同时,附加质量模型对地震中坝体内部应力及损伤也有一定的放大作用。可见,流固耦合模型分析大坝—水库系统相互作用更接近现实情况。

Comparative analysis on seismic damages of gravity dam obtained from two kinds of hydrodynamic pressure models

The impact from the reservoir water on the dynamic response of gravity dam as well as the stress distribution and the damages inside of the dam under strong earthquake is analyzed for the reservoir-dam coupling system with the displacement formulation-based fluid element and the solid element of elasto-plastic damage constitution. Through the comparison between the results of the analyses on the dam damages obtained from the fluid-solid coupling model and the added mass model respectively，it is found out that the added mass model not only overestimates the hydrodynamic pressure on the upstream surface of dam，but also enlarges the other dynamic responses of dam to a certain extent，such as displacement，acceleration，etc.，while the added mass model enlarges both the stresses and damages inside of dam during earthquake to a certain extent as well. Thus，it can be seen that it is more closely to the actual condition，if the interaction of the dam-reservoir system is analyzed with the fluid-solid coupling model.