海底滑坡作用下滩海管道结构安全分析  

Study on safety limits of the pipelines under submarine glide block

作　　者：姜诗源 盛积良 陈国明[1] 李新宏[1] 朱红卫[1] JIANG Shiyuan;SHENG Jiliang;CHEN Guoming;LI Xinhong;ZHU Hongwei(Centre for Offshore Engineering and Safety Technology,China University of Petroleum,Qingdao 266580,China;CCCC International Shipping Corporation,Tianjin 300451,China)

机构地区：[1]中国石油大学(华东)海洋油气装备与安全技术研究中心,山东青岛266580 [2]中交海洋建设开发有限公司,天津300451

出　　处：《海洋工程》2020年第2期128-134,共7页The Ocean Engineering

基　　金：国家重点研发计划课题“临海油气管道及陆上终端风险评估及防控技术”(2016YFC0802305)。

摘　　要：海底滑坡作为常见的海洋地质灾害,对海洋油气工程安全产生巨大威胁。海床土体失稳引起滑坡体滑动,会对海底管道产生拖曳作用。基于计算流体动力学方法(CFD)建立海底滑坡体对管道作用的评估模型,采用H-B模型描述块状滑坡体并与试验比较验证,分析不同海床倾斜度滑坡对管道的作用并拟合表达式;研究了海底管道在滑坡作用下的力学响应,并采用极限状态方法开展海底滑坡作用下管道结构极限安全分析,探讨了管道埋地状态时的极限安全界限,建立滑坡作用下管道结构安全分析方法。研究表明:滑坡对管道作用力与海床倾角呈现正相关,而覆土层厚度对作用力影响较小;随着不排水抗剪强度的减小,允许的滑坡宽度和速度均增加,表明土体不排水抗剪强度与引起的拖曳力呈正相关;滑坡土体宽度对极限安全速度影响较大。Submarine landslide is a common marine geological hazard,which has a great threat to offshore oil and gas engineering.Soil instability leads to mass sliding,which causes drag force on submarine pipelines.A model of the landslide and pipeline was established based on the computational fluid dynamics(CFD)method,and the H-B rheological model was selected to calculate the forces of landslides on the pipelines.The limit state method was used to calculate the safety range of the buried pipelinse under the action of submarine landslide,which can be used as a reference for engineering.Submarine landslide,a common marine geological hazard,may severely jeopardize the safety of marine oil and gas engineering.The sliding of landslide caused by the instability of soil in seabed will drag the submarine pipeline.In this study,an evaluation model of effect of submarine landslide on pipeline was developed based on the computational fluid dynamics method.The H-B model was used to describe the massive landslide and compared and verified with the experiment results.The effect of landslides with different seabed slopes on pipeline was analyzed and the expression fitted out.The mechanical response of submarine pipeline under the effect of landslides was also studied and the limit safety analysis of pipeline was presented by using the limit state method.The ultimate safety margin of the buried pipeline is also evaluated to develop the safety analysis method of pipeline under landslide.The results show that the force exerted by landslide on pipeline has a positive correlation to the seabed slope,while the thickness of overburden soil has little effect on the force.The permitted width and velocity of landslide increase with the decrease of undrained shear strength,indicating that the undrained shear strength of soil is positively correlated with the mobilized drag force.And the soil width of landslide induces a greater effect on the ultimate safe speed.

关 键 词：海底管道 海底滑坡 土体失稳 结构安全 安全界限 海床倾角 覆土层厚度 

分 类 号：TE52[石油与天然气工程—油气田开发工程]