Centrifuge Modeling of Cyclic Degradation of Axially Loaded Piles in Sand for Offshore Wind Turbine Structures

摘要

A centrifuge test program was designed to explore the influence of repeated cyclic loading on axial performance of pile foundations for jacket structures of offshore wind turbine systems. The program focused on low-amplitude, high-cycle (e.g., 10,000 to 100,000 cycles) loads meant to emulate conditions imposed during operation. The goals of this paper are to (1) demonstrate the feasibility of using a small centrifuge for this application, (2) present an initial data set from scaled centrifuge testing of piles subjected to one-way (tension) and two-way (tension and compression) cyclic axial loading, (3) evaluate the data set within an interaction diagram framework, and (4) provide guidance on implications of the findings and recommended next steps. Observations of the degradation of stiffness, the number of loading cycles to failure, and the evolution of the soil-pile interface friction at different depths are described.