ON THE MECHANICS OF PIPE WALKING: CASE OF A BURIED PIPELINE

摘要

The influence of soil sedimentation on the pipe walking phenomenon is investigated analytically via a set of coupled nonlinear partial differential equations where the effects of operating variables such as internal fluid temperature variation, prestress and internal pressurization, Coriolis and axial accelerations of the internal fluid and cross sectional area change are fully captured. For this problem, a segment of an offshore pipeline resting on the ocean floor is idealized as elastic beam on an elastic foundation using recently refined Euler-Bernoulli beam theory. By invoking integral transforms, closed form analytical expressions for displacement of the fluid-pipe-soil interaction system associated with pipe walking is computed. Simulated results showed that pipe walking phenomenon is strongly dependent on sedimentation level, friction at the interface of pipe-ocean sub soil layer, temperature variation, fluctuations in internal fluid pressurisation and oscillatory strain of the pipe in both transverse and longitudinal modes.