Lateral dynamic impedance of offshore elevated piles in layered soils
FU Peng1，2，HU Anfeng1，2，LI Long1，2，CHEN Yuan1，2，XIE Kanghe1，2
(1. Research Center of Coastal and Urban Geotechnical Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China；2. MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China)
Abstract：An analytical model，in which the dynamic pile-fluid interaction is considered，is proposed to investigate the lateral dynamic response of offshore elevated pile in layered soils. Firstly，on the basis of boundary conditions and radiation condition，the governing equation of water is solved by using separation variable method，and the solution for hydrodynamic pressure is derived. Considering the boundary condition，the governing equations of soil are solved by introducing potential functions，and the solution for dynamic soil reaction is derived. On the basis of the continuous condition at pile-fluid interface and pile-soil interface，the analytical solution of lateral dynamic response of offshore elevated pile in layered soils is obtained，and analytical expression of dynamic impedance of pile is also obtained. In order to verify the proposed solution，comparison with earlier solution is performed. Finally，a parametric study is conducted to investigate the effect of hydrodynamic pressure，water depth，soil modulus and soil layer thickness on lateral dynamic impedance of pile. The results show that water depth and property of surface soil have significant influence on the lateral dynamic impedance of offshore elevated pile. The analytical method ignoring the dynamic pile-fluid interaction overestimates the lateral dynamic stiffness of the pile.
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2019, Vol. 38 
