钢圆筒防护装置周围海床冲淤试验研究

Experimental study on scouring and siltation around steel cylindrical protective structures on seabed

通航区内水下油气生产系统需安装在海床下的钢圆筒防护装置内,以避免往来船舶抛锚、渔业活动等对油气开发设备产生破坏。为揭示海床下钢圆筒防护装置局部冲淤特性,同时验证工程设计方案的可靠性,基于通航区海床下水下生产系统钢圆筒防护装置,对周围土体冲淤特性开展试验研究。根据工程区域现场土样的级配资料配制现场土样,并对不同回填土质的水动力特性进行敏感性分析,得到不同回填土质临界起动流速,为工程回填材料选择提供参考。同时针对平整海床、凸出式和齐平式防护装置类型,开展模型试验研究。结果表明,基于工程场址土壤条件,在安装钢圆筒防护装置、设置回填材料等各种情况下冲淤量很小,均不会发生明显的冲淤现象。现场实测验证了设计方案冲淤试验结果的可靠性。研究结果可为海床下防护结构的设计提供参考。

In navigable areas,underwater oil and gas production systems need to be installed within steel cylindrical protective structures underneath the seabed to prevent damage from activities such as anchoring of passing ships and fisheries.This study aims to reveal the local scouring and siltation characteristics of the seabed beneath the steel cylindrical protective structures and to verify the reliability of the engineering design plans.Based on the steel cylindrical protective structures of the underwater production systems beneath the seabed in navigable areas,experimental research on the scouring and siltation characteristics of the surrounding soil was conducted.Field soil samples were prepared according to the grading data of the engineering area's onsite soil samples,and a sensitivity analysis of the hydrodynamic properties of different backfill soils was carried out to determine the critical initiation flow velocities of different backfill soils,providing references for the selection of backfill materials for the project.Model experiments were also conducted for flat seabed,protruding,and flush-type protective structure types.The results indicate that based on the soil conditions of the engineering site,the amount of scouring and siltation is minimal under various conditions such as the installation of steel cylindrical protective structures and the setting of backfill materials,with no significant scouring and siltation observed.Field measurements have verified the reliability of the experiment results on scouring and siltation of the design plan.The research findings can provide a reference for the design of protective structures underneath the seabed.