Earth pressure distribution on laterally loaded offshore monopiles

Abstract

<p>Unlike conventional pile foundations, a monopile is a large diameter open-ended steel tube driven into the seabed. Accurate quantification of the earth pressure distribution along a monopile due to <a href="https://www.sciencedirect.com/topics/engineering/lateral-loads" title="Learn more about lateral loads from ScienceDirect's AI-generated Topic Pages">lateral loads</a> plays a <a href="https://www.sciencedirect.com/topics/engineering/pivotal-role" title="Learn more about pivotal role from ScienceDirect's AI-generated Topic Pages">pivotal role</a> in the design of offshore <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/wind-turbine" title="Learn more about wind turbines from ScienceDirect's AI-generated Topic Pages">wind turbines</a> and remains a problem of great interest. This paper presents an attempt to address the problem by means of three-dimensional (3D) <a href="https://www.sciencedirect.com/topics/engineering/finite-element-modeling" title="Learn more about finite element modeling from ScienceDirect's AI-generated Topic Pages">finite element modeling</a>, with focus on the effect of pile slenderness on earth pressure distribution and the associated soil <a href="https://www.sciencedirect.com/topics/engineering/deformation-mechanism" title="Learn more about deformation mechanisms from ScienceDirect's AI-generated Topic Pages">deformation mechanisms</a>. The study shows that as <a href="https://www.sciencedirect.com/topics/engineering/pile-diameter" title="Learn more about pile diameter from ScienceDirect's AI-generated Topic Pages">pile diameter</a> increases, the <a href="https://www.sciencedirect.com/topics/engineering/deformation-mode" title="Learn more about deformation mode from ScienceDirect's AI-generated Topic Pages">deformation mode</a> of the pile will change from flexural to rotational deflection while the deformation pattern of the surrounding soil varies from being the wedge-type to a combination of the wedge-type and the rotation-type. The magnitude of either normal contact stress or shear stress at a pile section decreases with increasing <a href="https://www.sciencedirect.com/topics/engineering/pile-diameter" title="Learn more about pile diameter from ScienceDirect's AI-generated Topic Pages">pile diameter</a>, but the distribution pattern of the normalized contact stress (either normal or shear stress) is nearly the same. The implications of these findings for engineering practice are two-fold: (a) Use of the p-y relationship established from field tests on piles of reduced scales in the design of large-diameter piles may still result in a potential risk of overestimating the <a href="https://www.sciencedirect.com/topics/engineering/lateral-bearing-capacity" title="Learn more about lateral bearing capacity from ScienceDirect's AI-generated Topic Pages">lateral bearing capacity</a> if the test pile diameter is not large; and (b) a unified factor independent of pile diameter can be introduced to average the contact stress across the pile section in the development of simplified methods.</p>