考虑不同桩-土相互作用模型的海上升压站抗震性能分析

Seismic Performance Analyses on Offshore Substation with Different Pile-soil Interactions

由于海上升压站上部平台设有许多大质量专业设备,使其呈现“头重脚轻”的特征,直接借鉴传统海洋平台的设计方法难以准确评价海上升压站结构的承载能力与变形能力,其中桩-土相互作用对于地震作用下的结构动力响应分析的影响尤为显著。以国内某位于地震高烈度区的海上升压站为对象,分别基于等效线性桩长法、API规范p-y曲线法、修正p-y曲线法建立3种不同考虑桩-土相互作用的计算模型,对比中震作用下结构的抗震性能。结果表明,基于3种模型校核该海上升压站结构均符合抗震设防要求;海上升压站结构受竖向地震作用影响较明显;在砂土层占比较高的地基条件下,使用修正p-y曲线方法可以更合理地模拟桩-土相互作用。

Due to the large weight of the top platform structure,it is difficult to evaluate the bearing and deformation capacity of substations by the design method of traditional offshore platforms.Especially,pile-soil interaction plays a important role to seismic analyses of substations.An offshore substation located in high-intensity earthquake region was taken as research object.Refined FEM models with different pile-soil interaction models such as equivalent pile length method,API p-y curve method and modified p-y curve method were established to conduct the seismic analyses.The results showed that the offshore substation meets the seismic criteria;the vertical seismic responses have a great influence on the seismic performance of the substation structure;the modified p-y curve method can simulate the pile-soil interaction more reasonable in the foundations where sand layers take a large proportion.