罕遇地震作用下水电站厂房上部结构破坏模式研究

Failure modes of hydropower house superstructure under rare earthquake action

为揭示水电站厂房结构在罕遇地震作用下的破坏模式与抗震安全储备,基于ABAQUS平台,采用混凝土损伤塑性模型描述厂房混凝土,并通过子程序编程实现黏弹性人工边界以模拟无限地基,将人工波加速度峰值调整为罕遇地震对应的0.331g,针对某水电站厂房结构开展了动力非线性时程分析。结果表明,罕遇地震作用下厂房结构的破坏模式具体表现为下游立柱严重开裂、上游立柱开裂、上游墙底部开裂以及下游立柱出现轻微压损伤,混凝土损伤状态、钢筋应力、层间位移角均表明厂房结构自身具有较高的抗震安全储备,整体破坏程度在"可修"的水平。但上下游墙在顺河向的不协调运动会导致屋顶网架动应力非常突出,网架存在垮塌的风险,水电站厂房的抗震设计中应该充分重视屋顶网架与上下游墙的连接方式。

To reveal the failure modes and seismic a concrete damage plastic （CDP） model was used to safety margin of hydropower house under rare earthquake action, describe the concrete material and a viscous-elastic artificial boundary was adopted to simulate the infinite foundation. The peak acceleration of the artificial seismic wave is 0.331 g corresponding to the rare earthquake action. The dynamic nonlinear time-history analysis was carried out aiming at a practical hydropower house structure. The results show that, the failure modes of hydropower house under rare earthquake action are severe cracks in downstream columns, slight cracks in upstream columns, cracks in upstream wall and compressive damage in downstream columns. The concrete damage status, reinforcement stress and story drift angle indicate that the powerhouse has high safety capacity and the overall destruction is at the level of ＂repairable＂. However, because of upstream and downstream walls＇ inconsistent motion, the dynamic stress in roof net is very high and there exists risk of collapse. So the connection mode between roof net and upstream and downstream walls should be paid more attention in aseismic design of hydropower house.