极限安全地震作用下不同预应力工况对核安全壳地震反应的影响

Effect of Different Prestressed Conditions on Seismic Response of Nuclear Containment Structure under Ultimate Safety Ground Motion

为了研究极限安全地震作用下混凝土预应力对核安全壳结构地震反应的影响,本文设定仅考虑预应力的瞬时损失、考虑预应力的长期损失和孔道灌浆后预应力均布等3种预应力工况和无预应力工况,并建立核安全壳结构精细有限元模型,进行核安全壳结构地震反应的非线性时程分析。计算结果显示,极限安全地震作用下无预应力工况下安全壳结构在抗震薄弱位置产生大量贯穿截面厚度的裂缝,基本上进入了功能失效状态;而3种有预应力工况下安全壳结构整体处于弹性状态,但是在安全壳主要开洞区域产生了开裂,并且在预应力均布工况下核安全壳在筒身底部产生了一定数量的受拉裂缝。研究表明采用预应力混凝土结构能显著提高核安全壳结构的抗震能力,但设计中需要关注孔道灌浆后可能产生的预应力均布对核安全壳结构抗震安全性能的不利影响。研究结果可为核安全壳结构设计合理利用预应力混凝土的抗震优势提供指导。

In order to study the influence of prestressed conditions of concrete structure on the seismic response of the nuclear containment structure under ultimate safety ground motion,in this paper,only three prestressed conditions,which are instantaneous prestress loss,long-term prestress loss and uniform distribution of prestress after duct grouting,and the no prestressed condition are considered,and then the nonlinear time history analysis of the seismic response of the nuclear containment structure is conducted by establishing their refined finite element models.The simulation results show that for the no prestressed condition,the containment structure has a large number of cracks running through the thickness of the section in the weak seismic position under ultimate safety ground motion,and the structure basically enters the state of functional failure;while the whole containment structure is in an elastic state under the three prestressed conditions.However,cracks occur in the main opening areas of the containment,and a certain number of tension cracks are generated at the bottom of the containment body under the condition of uniform prestress distribution.The research shows that the prestressed concrete structure can significantly improve the seismic capacity of the nuclear containment structure,but it should be paid attention to the adverse impact of the uniform prestress distribution that may occur after the duct grouting on the seismic safety performance of the nuclear containment structure in design.The research results can provide guidance for the rational use of the seismic advantages of prestressed concrete in the design of nuclear containment structure.