重力式沉箱码头在双向振动下的地震响应有限元分析

FEM investigation of seismic response of caisson-type quay wall subjected to bidirectional shaking

重力式码头的抗震设计是港口水工建筑物地震响应研究的重要课题。基于ABAQUS有限元软件按照神户重力式码头PC1泊位沉箱的实际参数设计二维模型,用港岛地下32 m深处的实测地震加速度作为输入波形,考虑了码头结构-地基的相互作用、地震波的双向耦合以及无限元边界的滤波作用。研究结果表明:沉箱顶部海侧角的水平残余位移为2.53 m,竖向沉降稳定在1.11 m,与实测数据相比误差控制在1.7%之内,验证了模型的准确性;沉箱前趾与后踵周围地基土体已经发生塑性屈服,前趾下的地基土为应力集中区域,等效应力峰值达到0.8 MPa,是抗震设计中需要注意的部分。

The seismic design for the gravity quay wall is an important research for hydraulic structures. A 2D numerical model, representing PC1 berth located in Port Island, Kobe, which was damaged in the 1995 Kobe earthquake, is developed by ABAQUS to simulate the seismic behavior. This paper considers the interaction between soil and structure, and the role of wave filtering by infinite element boundaries. The results show that the horizontal displacements and vertical settlements at caisson top＇s sea side are 2.53 m and 1.11 m respectively. Compared with the measured data, the error is controlled within 1.7%. This verifies the accuracy of the model. The plastic damage in the foundation is the main reason for the structural damage. Soil under the front toe of caisson is stress concentration area and should be paid attention to. The peak equivalent stress in this area, which shall be paid attention to in the seismic design, reaches 0.8 MPa.