摘要
在2006-2009年某气田群海底管道路由调查中,发现海底管道处于不同程度的冲刷状态,严重威胁管道的安全。提出该气田群海底管道的冲刷成因主要是:在海底管道周围较高流速的流场作用下产生涡旋-马蹄涡和尾涡,该种涡旋易在多孔土壤环境中形成渗流,继而造成管涌和流土现象。通过实验证明粘土质海床与砂质海床的冲刷机理存在不同,并总结影响粘土质海床局部冲刷的因素。研究表明淤积不久、强度较小的土体在冲刷作用下可能发生流土现象,但对固结时间较长的粘土则不足以促使流土形成。另外,考虑到水流与管道的夹角因素,提出了粘土质海床冲刷坑沿管道扩展的近似计算公式。同时,简要介绍了支撑管道、沙袋填充、仿生结构覆盖和重新挖沟4种海底管道修复方案。
An investigation during 2006-2009 on the submarine pipeline route in a gasfield showed that varying degrees scouring on the pipeline was found.This kind of scouring seriously threatened the safety of pipeline.The main reason for the scouring was the horseshoe vortex and trailing vortex generated under the action of high-speed flow field around the submarine pipeline.In the porous soil environment,this kind of vortex formed seepage flow easily,and 'piping'afterwards.Experiments displayed that the scouring mechanism between cohesive seabed and sandy seabed was different.And the factors influencing local scouring on cohesive seabed were summarized.It was also found in experiments that the'piping'was easier to happen in the soil deposited soon with less intensity,which was different in the cohesive soil deposited for a long time.Furthermore,considering the angle between water flow and pipeline,an approximate calculation formula was proposed for scouring pit expanding along pipeline on the cohesive seabed.Four kinds of submarine pipeline rehabilitation technologies such as supporting pipeline,filling sandbags,covering by bionic structure and re-excavation were introduced briefly.
出处
《油气储运》
CAS
北大核心
2011年第5期376-380,317,共5页
Oil & Gas Storage and Transportation
关键词
海底管道
海床
悬跨
冲刷
修复
submarine pipeline,seabed,span,rehabilitation
