This paper presents the results of a series of physical experiments to quantify the drag force on a submarine pipeline caused by a glide block or an out-runner block impact normal to the pipe axis. The experiments were carried out in a geotechnical centrifuge at C-CORE under submerged conditions at a centrifugal force of 30 times the Earth’s gravity (i.e. N = 30) and simulated steady and uniform impact velocities ranging between 0.1 and 1.3 m/s with the soil blocks being approximately 5 m in height in prototype scale. The soil blocks were made of kaolin clay consolidated to have undrained shear strengths ranging between about 4 and 6 kPa. The diameter of the model pipes were 6.35 and 9.5 mm corresponding to about 0.19 and 0.29 m in prototype terms. The shear strain rates, defined as the ratio of impact velocity to pipe diameter, in the centrifuge model are N times higher than that in the prototype. The shear rates simulated ranged from about 10 to 136 reciprocal seconds. The paper presents a method for estimating block impact drag force on submarine pipelines based on the results of the centrifuge experiments.
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