Deep sea water pumping pipe destruction due to undersea debris flow

Abstract Background This study investigates the destruction of deep-sea water pumping pipes due to submarine debris flows. The DEBRIS- 2D debris flow simulation model is applied to an actual submarine debris flow case in the Zhi-Ben River Estuary in Taitung County, Taiwan. Results Simulation results show that the submarine debris flow progresses at a speed of less than 10 cm/s, and its depth increases in deeper regions. Due to topographical changes, there is a rapid increase in flow depth when the debris flow approaches a small sea ridge. This rapid change in depth induces significant pressure differences on pipeline connections located just below, leading to their destruction. A substantial pulling force is exerted on the pipeline due to its long-submerged length under moving debris flows. This pulling force induces the failure of pipe joints upstream of the debris flow-submerged area. The failure locations calculated from the simulation align closely with field investigations, confirming that the pipeline’s destruction was caused by submarine debris flows. Conclusion The findings indicate that submarine debris flows can be hazardous to pipelines due to seabed geological variations during transient motion stages. Given that these hazards stem from debris flow dynamics and seabed topography, it is recommended that pipeline installations incorporate submarine debris flow simulations to mitigate such risks.