Drag forces caused by submarine glide block or out-runner block impact on suspended (free-span) pipelines

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• 作者：Arash Zakeri^a ; ^{arash.zakeri@c-core.ca} ; Bipul Hawlader^b ; Ken Chi^a ; ^b
• 关键词：Submarine glide block ; Submarine out-runner block ; Impact ; Pipeline ; Drag force ; Centrifuge modeling
• 刊名：Ocean Engineering
• 出版年：2012
• 期刊代码：133_00298018
• 类别：et
• 出版时间：June, 2012
• 卷：47
• 期：Complete
• 页码：50-57
• 文件大小：618 K

摘要

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 are presented. The experiments were conducted in a geotechnical centrifuge under submerged conditions at a centrifugal force of 30 times the Earth's gravity (i.e. N=30) and simulated impact situations under steady state conditions and uniform velocities. The soil blocks (approximately 4.5 m high in prototype terms) were made of kaolin clay with undrained shear strengths between 4 and 8 kPa. The model pipes were 6.35 and 9.52 mm in diameter (0.19 and 0.29 m in prototype terms). The impact velocities ranged between 0.04 and 1.3 m/s. The pipe centerline was at mid-height of the block. The shear strain rates, defined as the ratio of impact velocity to pipe diameter. The shear strain rates ranged from about 4 to 137 reciprocal seconds. Hence, the test results are applicable to a wide range of field situations. A method is presented for estimating glide or out-runner block impact drag force on submarine pipelines based on the results of the centrifuge experiments.