管线J型铺设下放过程受力影响因素分析

采用J型铺管系统进行深水管线铺设时,管线在环境载荷作用下于铺设塔分离位置产生较大的弯矩,因此需要根据管线入水长度的增加而不断调整铺设塔工作角度以保证施工安全.本文以我国拟建造的半潜式J型铺管平台为目标船,以管线由水面下放铺设至海底的过程为对象,采用水动力软件OrcaFlex建立计算模型.在静态条件下分析铺设角、流向角对...

Analysis on influencing factors of pipeline stress during the lowering process of J-Lay

When J-Lay system is used for deepwater pipeline laying,the pipeline will produce large bending moment at the separation position of laying tower under the action of environmental loads.Therefore,the working angle of laying tower needs to be adjusted continuously according to the increase of subsea pipeline length to ensure the construction safety.By taking the semi submersible J-type pipe laying platform to be built in China as the target ship,and the process of pipeline laying from the surface to the seabed as the object,a computational model is established by using the hydrodynamic software OrcaFlex.The influence of laying angle and flow direction on pipeline stress under static conditions is analyzed in order to obtain the appropriate laying angle for different laying length.Under dynamic conditions,the effects of ship heave,sway,roll and pitch on the stress at key positions of the pipeline are studied.The results show that the ship motion has a great impact on the stress at the contact position of the pipeline stinger when the pipeline is lowered to the seabed.After the pipeline is laid on the seabed,only the heave motion has a significant impact on the stress in the touchdown point area.The analysis on the influencing factors of pipeline stress during the whole process of J-Lay in this paper can provide a theoretical basis for the design of actual deepwater pipeline laying.