SV波斜入射下混凝土重力坝易损性分析  

Fragility analysis of the concrete gravity dam under the oblique incidence of SV waves

作　　者：刘金芳 尹晓霞 高凤 LIU Jinfang;YIN Xiaoxia;GAO Feng(Qinghai Water Resources and Hydropower Survey,Planning,Design and Research Institute Co.,Ltd.,Xining 810012,Qinghai,China;Qinghai Bureau of Animal Husbandry and Agriculture Accounting Assignment Center,Xining 810012,Qinghai,China;Architecture Zabor University of Shaanxi Province,Xi'an 710043,Shaanxi,China)

机构地区：[1]青海省水利水电勘测规划设计研究院有限公司,青海西宁810012 [2]青海省农田建设和土地整治中心,青海西宁810012 [3]陕西省建筑职工大学,陕西西安710043

出　　处：《地震工程学报》2024年第2期318-324,334,共8页China Earthquake Engineering Journal

基　　金：西安市碑林区应用技术研发项目(GX2150)。

摘　　要：易损性分析是评估不同强度地震作用下混凝土重力坝各级破坏概率的有效方法。目前重力坝易损性分析通常假定地震波为垂直入射,然而在近断层区域,地震波往往是倾斜入射的,地震波斜入射对重力坝地震响应有显著影响。从太平洋地震工程研究中心数据库选取16条地震动记录,采用黏弹性人工边界结合等效节点荷载实现SV波斜入射波动输入。采用增量动力分析方法对地震动峰值加速度进行调幅,以印度Koyna混凝土重力坝为研究对象,以坝顶相对位移为抗震性能指标,建立SV波斜入射下重力坝不同震损等级的易损性曲线。结果表明,与垂直入射相比,相同震损等级和相同地震动强度下,斜入射时重力坝破坏概率减小;当PGA接近重力坝实际遭受的地震动强度时,入射角为15°和30°时破坏概率与垂直入射相比最大减小率分别为27.3%和68.2%;各地震强度下,15°和30°斜入射相对于垂直入射的破坏概率差异值最大分别达36.6%、83.9%。因此,混凝土重力坝抗震性能分析应考虑地震波斜入射的影响。研究结果也可为近断层区域混凝土重力坝安全风险评估提供参考。An effective method for evaluating the damage probability of concrete gravity dams under ground motions with different intensities is fragility analysis.The fragility analysis of gravity dams generally assumes that seismic waves are vertically incident,but those in the near-fault area are obliquely incident.The oblique incidence of seismic waves has a considerable influence on the seismic response of gravity dams.Based on the database of the Pacific Earthquake Engineering Research Center,16 ground motion records were selected,and the oblique incidence input of SV waves was realized using the viscoelastic artificial boundary and equivalent nodal load.The PGA of ground motion was modulated using the incremental dynamic analysis method.The Koyna concrete gravity dam in India was taken as the research object in this paper.The fragility curves for different earthquake damage levels of the gravity dam under the oblique incidence of SV waves were established by taking the relative displacement of the dam crest as the seismic performance index.Results show that under the same earthquake damage level and ground motion intensity,the damage probability of gravity dams under the oblique incidence of SV waves decreases compared to that under the vertical incidence.When the PGA is close to the actual earthquake intensity of gravity dams,the maximum reduction rates of failure probability are 27.3%and 68.2%,respectively,when the incident angles are 15°and 30°,compared with that under vertical incidence.Meanwhile,the maximum difference values of failure probability are 36.6%and 83.9%compared with those under vertical incidence.Therefore,the influence of the oblique incidence of seismic waves should be considered in the seismic performance analysis of concrete gravity dams.The results can also provide a reference for the safety risk assessment of concrete gravity dams in near-fault areas.

关 键 词：混凝土重力坝 地震波入射角度 增量动力分析 黏弹性边界 相对位移 

分 类 号：TV312[水利工程—水工结构工程]