Response of buried pipeline subjected to reverse faulting

Abstract

The paper studies the interaction of buried pipelines with a reverse fault rupture, employing 3D finite element (FE) modelling. A thoroughly validated strain softening constitutive model is employed to conduct a parametric study, exploring the effect of sediment thickness, pipeline burial depth and thickness. It is shown that the increase of sediment thickness H leads to a reduction of the normalized fault offset h/H at which buckling is initiated. Two contradicting mechanisms are identified: (i) the increase of H leads to a reduction of the intersection angle α of the fault rupture with the pipe, increasing the compressive component; and (ii) it leads to a reduction of localized deformation close to the surface. From our results, the h/H required for initiation of buckling is insensitive to burial depth Hp/D, but the one required for pipe rupture increases substantially with increase of Hp/D. The increase of the D/t (pipe diameter to wall thickness) ratio leads to a substantial decrease of the h/H at which buckling is initiated, and the same applies to the pipe rupture criteria, which are met at a smaller h/H with the increase of D/t.