Submarine pipelines are often hit by third-party loads, resulting in pipeline rupture and eventually causing huge economic losses. In order to prevent the damage to the submarine pipeline from the emergency anchor operation, it is necessary to protect the pipeline. Based on the ANSYS/LS-DYNA software, firstly, a finite element model for the process of the anchor from air into the water is established. By setting different weight, height and depth of anchor, this paper gets the variation in water velocity, different grounding velocity. Then, another finite element model for the process of the anchor gets into the seabed is established. By setting different weight, grounding velocity and seabed sediment, this paper obtains the damage degree of the pipeline, provides a theoretical basis for submarine pipeline safety embedding. The research results can not only protect the pipeline from the damage of anchoring but also save the cost of laying pipeline, which is of great practical significance.
As the main transportation channel of oil and gas, submarine pipelines play an important role in offshore oil and gas resources exploitation and operation. Because of its advantages of economic, quick and large volume, submarine pipelines have been widely applied, and have become the main force of world oil and gas storage and transportation engineering construction. With the rapid development of new energy in recent years, the submarine pipelines will play an important role in the transportation of new energy. However, With the increase of the number and tonnage of ships, the accidents of ship's accidental anchoring are also increasing. This poses a serious threat to the safety of submarine pipelines laid near the route. If the ship is out of control in the vicinity of the submarine pipeline, the anchor may hit the submarine pipeline. The failure of the emergency anchor to hit the pipe may cause the pipeline to break and cause oil and gas leakage accidents. The leakage of oil and gas will not only pollute the surrounding waters, but also harm the Marine life, making it difficult for the Marine environment to recover the ecological ability for a long time. And once the oil and gas is ignited, there will be an explosion, leaving hidden danger to the life safety of people who are engaged in underwater activities in the nearby waters (Yan SW, Zhuo RH, Wang WG, Yang Y, 2012). In this paper, a finite element model for the whole process of the anchor from air into the water to the anchor into the seabed is established by using ANSYS/LS-DYNA software, and the velocity variation of the anchor in the water as well as the stress variation of submarine pipelines when anchor penetrates into seabed are analyzed. Based on this, this paper proposes a new method to determine the damage degree of the submarine pipeline under the impact of the anchor, which provides a theoretical reference for the protection of the submarine pipeline. This is of great significance to the exploitation and transportation of offshore oil and gas.
