Prediction of the Behaviour of Monopiles Under Drained Two-Way Cyclic Lateral Loading in Sand

Abstract

The monopile is considered as one of the preferred geotechnical foundations for the offshore wind energy converter; therefore, its cyclic behaviour is one of the major concerns in the design. In the current design approaches, the prediction of two-way cyclic behaviour mainly depends on empirical equations, in which the specific site conditions are not considered. Therefore, quantifying the cyclic behaviour of monopiles under two-way cyclic loading is still an issue under research. In this sense, the numerical method cyclic strain accumulation method (CSAM), which has already been validated on monopile and shallow foundations subjected to one-way cyclic loading in sand under drained conditions, is modified and applied to monopiles under two-way cyclic loading. Through the comparison between the numerical results and measurements on a small-scale test and a numerical investigation on a prototype monopile, it has been shown that the CSAM is capable of giving realistic predictions of the two-way cyclic behaviour of the monopiles and thus provides a new promising tool to describe the two-way cyclic behaviour of the monopiles, taking into account site-specific conditions.