低承台群桩动力阻抗的有限元分析

Finite Element Analysis of Dynamic Impedances of Pile Groups with Embedded Caps

采用有限单元法分析承台埋置在土中的群桩的动力阻抗.采用透射边界来模拟土的辐射阻尼,计算了2×2群桩和3×3群桩的竖向、水平和摇摆动力阻抗.分析表明,承台的埋置对群桩的水平和摇摆动力阻抗有很大的影响.与高承台群桩相比,低承台群桩动力阻抗在某一频率范围内可能大很多,但在另一频率范围内也可能小,呈现出复杂的频率相关性.

Finite element (FE) analysis were performed to investigate the dynamic impedances of pile groups, the caps of which were embedded in soil. The transmitting boundary was employed to simulate the geometrical damping of soil. The vertical, horizontal and rocking dynamic impedances of a 2×2 and a 3×3 pile group are presented. The analysis indicate that the embedment of pile caps has considerable effect on the horizontal and the rocking impedances of pile groups. Compared with elevated pile groups, the impedances of pile groups with embedded caps may be much greater in a frequency range but less in other frequency ranges, which displays complicated frequency-dependence.