Numerical analysis of pipe–soil interaction between SCR and nonlinear seabed based on co-rotational approach

Abstract

ABSTRACT This paper proposes a numerical model for analysing the vertical pipe-soil interaction between SCR and nonlinear seabed in the touchdown zone, which is subjected to complex stress concentration effects. The model establishes a co-rotational coordinate system of the riser and simulates pipe-soil interaction using a series of springs based on p-y backbone curve. The global displacement of the riser and the resistance of the seabed soil are coupled and solved iteratively by the Newton-Raphson method. The result shows that this approach can solve the initial penetration of the riser in the touchdown zone. Parametric analysis reveals that riser with larger length and thickness-to-diameter ratio, the deeper embedment in the seabed, also the larger response of the seabed soil resistance at the same time. Estimation functions are developed by polynomial fitting method to analyse the relationships between length to diameter ratio (L/D) of the riser and standardised embedment, standardised soil resistance.