Analysis of pipeline-sediment interaction under vertical loads

Vertical static, monotonic, and cyclic load tests were conducted using a model pipe to model the behavior of pipe-sediment interaction. The model tests were carried out on a viscoelastic sediment with shear strengths similar to the soft sediments found in the Gulf of Mexico. Finite element method analyses of the pipe under static and monotonic loading conditions were performed using the ABAQUS computer code. Experimental and finite element results compared well with a theoretical model developed earlier.;Based on the experimental results a pipe-sediment interaction model was developed to predict the pipe embedment under static and cyclic loading conditions. The magnitude of pipe embedment under cyclic compressive force tests was smaller than under alternating compression and suction force cyclic tests. In the case of tests conducted with water cover the magnitude of pipe embedment was larger than without water. The higher embedment was due to the physical removal of the sediment around the pipe due to erosion. Sediment erodibility characteristics have significant influence in the magnitude of pipe embedment under water.;The ABAQUS finite element code was used to model the pipe under monotonic and static loading conditions. An elasto-plastic constitutive model was used to represent the sediment in this analysis. The finite element results infer that the width of the sediment system has a greater influence than the thickness of the sediment on pipe force-embedment relationship. At least nine pipe diameters width and two pipe diameters thickness of the sediment for a maximum pipe penetration of half the diameter is required to essentially eliminate boundary effects on the pipe behavior.