Analysis of lateral bearing mechanism for offshore monopiles in sand and development of an analytical method.

Revealing lateral soil bearing mechanism around an offshore monopile is critical for understanding and solving soil-pile interactions. In this paper, the lateral bearing mechanism around an offshore monopile in sand is analyzed and a corresponding analytical method is established. Three soil bearing mechanisms, including wedge-type flow, triaxial extension and volume compression, near mudline under working load level are proposed by analyzing the distribution of the Lode's angle (θ L) and soil displacement vectors. A corresponding analytical method to calculate the lateral response of the monopile is developed based on the strain wedge (SW) model. The proposed model is verified through three pile tests. Finally, the effect of the parameters of Duncan-Chang model on the monopiles in dry and saturated sand is discussed. • Wedge-type flow, triaxial extension, and volume compression around a laterally loaded monopole are clarified. • The reasons for the formation of the three soil bearing mechanisms are explained. • A simplified analytical method considering the three soil bearing mechanisms is established to calculate monopile behaviors. • The clarification of the soil bearing mechanisms is useful for understanding and solving soil-pile interactions. [ABSTRACT FROM AUTHOR]