Cyclic Lateral Load Tests on Pile Segments in Sand

Abstract

The rapidly growing offshore wind energy industry is expanding to areas with difficult soil conditions such as seismically active regions offshore Japan and Taiwan. Pile foundations, whether as a monopile or in jackets or tripods are mainly used to support offshore wind turbines. However, designers face numerous challenges related to predicting long-term performance of these foundations in problematic soils, especially under cyclic loading, with the risk of significant accumulated displacement or tilt. These risks are exacerbated by occasional storm surges and possibly seismic events. This paper presents an experimental device that models a miniature instrumented pile segment in sand under cyclic loading and can measure the soil reactions and excess pore pressures that may develop. The device allows the simulation of storm events and the study of various mechanisms that may occur in the soil, including cyclic degradation, strain degradation, pore pressure generation, rate effects, gapping and ratchetting. The soil reaction curves obtained during the testing could be adopted to calibrate finite element or other models