ジャッキアップリグの波浪中着離底作業時の脚部衝撃力に関する研究(第一報)

概要

論文の詳細を見る
In the installation and retrieval operations of a jack-up rig, its legs may be subjected to impact forces from the sea bottom due to rig's motions in waves, and a severe collision may lead to the formation of the damages on legs and/or jacking mechanisms. To avoid these damages, several operation manuals restrict a sea-state where such operations can be performed safely to 1.5m in wave height. This standard, however, is not always relevant because it's determined with no relation to an incident wave period and a rigidity of the sea bottom. An excessively conservative standard leads to much down time in operation. Then, both from structural and operational points of view, it is important to predict the impact forces more accurately and establish the more acceptable standard. In this study, experiments on a model rig subjected both to vertical and horizontal reaction forces from bottom were carried out in regular waves. Theoretical analyses in time domain were also performed using a newly developed analytical model where legs were treated as elastic bodies. From both results, several basic characteristics of behaviors of a rig and impact forces in legs at collision were obtained, and simultaneously, the applicability of the analytical model was demonstrated. Furthermore, through the theoretical analyses, some case studies on a proto-type rig were carried out.
社団法人日本船舶海洋工学会の論文
1986-03-01