- 摘 要
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（1 大連理工大學海岸與近海工程國家重點實驗室， 大連 116024；2 大連理工大學建設工程學部水利工程學院工程抗震研究所， 大連 116024）
［摘要］為研究水平變剛度優(yōu)化設計對樁筏基礎動剛度的影響，針對成層地基上的大型樁筏基礎，采用直接法計算樁筏基礎模型在水平、豎直和回轉三個方向上的動阻抗函數(shù)。對比分析了不同地震動水平下，變樁徑和變樁距對樁筏基礎動阻抗函數(shù)的影響。結果表明，水平變剛度優(yōu)化設計和地震動水平對所研究樁筏基礎動阻抗函數(shù)的影響隨輸入頻率的變化而變化。當輸入頻率較小時，水平變剛度優(yōu)化設計對樁筏基礎三個方向動剛度的影響均不明顯，當輸入頻率較大時，樁筏基礎水平方向動剛度會減小，但豎向和回轉方向的動剛度不受影響；地震動水平的增加會減小土體的等效剪切模量、增加土體的等效阻尼比，進而減小樁筏基礎動阻抗函數(shù)曲線的振蕩幅值。建議對樁筏基礎進行不同輸入荷載頻率的研究，以確保優(yōu)化設計的可靠性。
［關鍵詞］樁筏基礎；動阻抗；水平變剛度優(yōu)化設計；變樁徑；變樁距
中圖分類號：TU473文獻標識碼：A文章編號：1002-848X(2021)06-0129-06
Influence of horizontal variable rigidity optimization design on dynamic impedance of piled raft foundation
XIE Yunfei1,2, CHI Shichun1,2, WANG Maohua1,2
(1 State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China;2 Institute of Earthquake Engineering, Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, China)
Abstract:In order to study the influence of horizontal variable rigidity optimization design on dynamic stiffness of pile raft foundation，for large piled raft foundation in layered soils, the direct method was used to calculate the dynamic impedance function of the piled raft foundation model in three directions of horizontal, vertical and rotational directions. The influence of optimization design with variable pile diameter and variable pile spacing on the dynamic impedance function of the piled raft foundation under different earthquake ground motions was analyzed. The results show that the influence of horizontal variable rigidity optimization design and ground motion level on the dynamic impedance function of piled raft foundation varies with the change of input frequency. When the input frequency is small, the influence of the horizontal variable rigidity optimization design on the dynamic rigidity of pile raft foundation in three directions is not obvious. When the input frequency is large, the horizontal dynamic rigidity of pile raft foundation decreases, but the vertical and rocking dynamic rigidity is not affected. The increase of ground motion level can reduce the equivalent shear modulus of the soil and increase the equivalent damping ratio of the soil，which reduce the oscillation amplitude of the dynamic impedance function curve of the piled raft foundation. It is suggested that it is necessary to study the different input load frequencies of pile raft foundation in order to ensure the reliability of optimization design.
Keywords:pile raft foundation;dynamic impedance;horizontal variable rigidity optimization design;variable pile diameter;variable pile spacing
作者簡介：謝蕓菲，博士研究生，Email：xieyunfei@mail.dlut.edu.cn。
