Centrifuge modelling of active slide–pipeline loading in soft clay

Abstract

Submarine slides are a significant hazard to the safe operation of pipelines in the proximity of continental slopes. This paper describes the results of a centrifuge testing programme aimed at studying the impact forces exerted by a submarine slide on an offshore pipeline. This was achieved by dragging a model pipe at varying velocities through fine-grained soil at various degrees of consolidation, hence exhibiting properties spanning from the fluid to the geotechnical domains, relevant to the state of submarine slide material. To simulate the high strain rates experienced by the soil while flowing around a pipe in the path of a submarine slide, tests were conducted at pipe-soil velocities of up to 4 . 2 m/s. The changing density and shear strength of the samples were back-calculated from T-bar penetrometer test results. A hybrid approach combining geotechnical and fluid-mechanics-based components of horizontal drag resistance was developed. This approach provides an improved method to link the density and strength of the slide material to the force applied on the pipe. Besides fitting the present observations, the method provides an improved reinterpretation of similar data from the literature.

A semi-analytical method of stress-strain analysis of buried steel pipelines under submarine landslides

“…Zakeri [4] provided a review of work in this area. Sahdi et al [7] performed a centrifuge test to analyze the impact force of a submarine landslide on an offshore pipeline.…”

Impact forces of submarine landslides on offshore pipelines

“…Boukpeti et al (2012b) continuously extended the geotechnical characterization of finegrained sediments into the liquid range and proposed a combined model that could simulate the full process of submarine landslides. Sahdi et al (2014) proposed a hybrid approach that combined geotechnical and fluid-mechanics-based components of the horizontal drag resistance. This approach provided an improved method to link the density and strength of the landslide material to the force applied on the pipe.…”

Offshore Natural Gas Pipelines Subjected to Kinematic Distress

“…Zakeri et al [2,3], taking into account experimental data, derived analytical expressions for calculating the drug force on the pipelines depending on the soil conditions, the slope angle, the intersection angle, etc. Subsequently, Randolph & White [4] and Liu et al [5] improved initial flaws of the analytical formulas taking into account additional parameters, while Sahdi et al [6] investigated the problem via centrifuge experimental models.…”