Force Calculation and Analysis on Salvaging of Faulted Submarine Cables Considering Submarine Topography and Soil Mulch

Salvage of submarine cable is a very important step in their troubleshooting. It is necessary to ensure the safety of the salvage and avoid secondary damage to this submarine cable. A force model is established for the salvage process of submarine cable, and it is analyzed the effects of water depth, slope, uplift, and low-lying terrain on the curvature and force of the salvaged submarine cables. At the same time, it also analyzes the impact of cable surface cover cleaning on the salvage process. Calculations indicate that, during the cable salvage, the tension of the lifting point needs to be strictly controlled when lifting, as it is the largest force bearing point for regular cables. The paper provides a control range for the angle of the cable at the lifting point, which needs to be maintained at different lifting heights to control the angle of the lifting point and always remain within this range to avoid cable bending failure. It is obtained from the simulation that, the length of cable bending failure increases with the increase of routing slope, and as the routing slope increases, the water depth at the location where the submarine cable leaves the site decreases, resulting in a decrease in the maximum effective tension. Meanwhile, it can be concluded that when the speed ratio is large, the influence of seabed uplift height can be ignored, and when the cable salvage passes through low-lying areas, the extreme curvature values are distributed at the front end of the cable and at the turning points from the downhill section to the horizontal seabed. In addition, calculations have shown that during the salvage process, the state of the cover has a small impact on the tension of the submarine cable, but a significant impact on the curvature of the submarine cable. In the incomplete cleaning section of the cover, the minimum bending radius of the submarine cable may exceed the limit that the submarine cable can carry, causing damage to the submarine cable.