可液化场地20万吨级卸荷式板桩码头地震反应分析

Seismic analysis of 200,000 tonnage sheet-pile wharf with relieving platform in liquefiable ground

地震作用下场地液化是码头结构发生破坏的主要原因之一。针对一种20万吨级卸荷式板桩码头建立二维有限元数值模型,采用有效应力法对该码头结构进行动力时程分析,研究其在可液化场地条件下的受力变形特征以及周围土体的动力反应。结果表明:可液化场地条件下,板桩码头的前墙变形与传统单锚式柔性挡墙不同,未出现明显的凸胀变形;地震作用过程中前墙承担的弯矩最大,最大弯矩位于海底泥面附近;码头结构对周围土体的地震反应有放大效应,临空面对土体地震动峰值加速度(PGA)影响范围随地震强度的增加有减小的趋势;墙后填土液化范围随地震动强度的增加逐渐扩大,在0.50 g情况下存在整体滑移的危险。

The liquefaction of ground is one of the main reasons for the destruction of the wharf structure under seismic action.A two-dimensional finite element numerical model is established for a type of 200,000-tonnage sheet-pile wharf with relieving platform,and the effective stress method is applied to analyze the dynamic time-history of the wharf structure,its force and deformation in liquefiable ground and the dynamic response of the surrounding soil are analyzed in details.The results are summarized as following:in the liquefiable ground,the deformation of the front wall of the new type of sheet-pile wharf is different from that of the traditional single anchored flexible retaining wall,and there is no obvious bulging deformation.The bending moment of the front wall is the largest in the seismic action,and the maximum bending moment is located near the sea floor.The structure of the wharf has magnified effect on the seismic response of the surrounding soil,and the influence of the empty face on the PGA decreases with the increase of the earthquake intensity.The soil liquefaction range increases with the increase of ground motion intensity,and there is a risk of overall slip in the case of 0.50 g.