考虑材料老化的加高重力坝地震动力响应分析

Seismic dynamic response analysis of heightened gravity dam considering material aging

混凝土坝的动力响应随着混凝土龄期的增加、性能的退化会发生显著变化,而加高重力坝还受到新老混凝土材料差异的影响。为研究重力坝运行期材料老化和加高重力坝新老混凝土性能差异对地震作用下动力响应特性的影响,以加高的丹江口重力坝为例,利用ABAQUS有限元分析软件进行地震动力响应分析。同时,对比加高重力坝、拆除重建重力坝(即材料全新工况)以及按加高高度建造重力坝(即材料全老工况)3种工况下的地震响应情况,分析加高重力坝在地震动力下随着混凝土材料性能老化的坝顶位移、关键点应力和塑性损伤的响应。研究结果表明:随着混凝土材料老化程度增加,加高重力坝坝体的动力响应总体优于材料全老工况,同时劣于材料全新工况;其中坝体损伤呈经老坝折坡处后向新老混凝土结合面向下延伸的趋势。加高重力坝可适应结构变化后的受力和变形,同时兼具损伤破坏指标低、抗滑稳定性系数高的特点,坝体综合抗震性能得到提高。

With the increase of concrete age and performance degradation,the dynamic response of concrete dam will change significantly.The heightened gravity dam is also affected by the difference between new and old concrete materials.In order to study the influence of the aging of gravity dam materials and the performance difference of new and old concrete in heightened gravity dams,taking the heightened Danjiangkou gravity dam as an example,the seismic dynamic response analysis is carried out by using the ABAQUS finite element analysis software.The demolition and reconstruction(the new material condition)and the construction according to the heightened height(the old material condition)are compared with the heightened condition,analyzing the responses of heightened gravity dams to the displacement of the crest,the stress at key points,and the plastic damage with the aging of the concrete material properties under seismic dynamics.The results show that with the increase of the aging degree of concrete materials,the dynamic response of the heightened gravity dam is generally better than that of the old materials and inferior to the new materials.The damage of the dam body tends to extend downward to the joint surface of the new and old concrete.The heightened gravity dam has the characteristics of strong adaptability,low damage index and high anti-sliding stability coefficient,which improve the comprehensive characteristics of the dam body.Besides,the weak parts such as the new and old joint surfaces should be reinforced and bonded to give full play to the engineering benefits of heightening the gravity dam.