The sinkage of underwater landing robots deployed on loose seabed sediment over extended periods poses a significant challenge. Excessive sinkage can significantly reduce the locomotion performance of robots or even cause them to become trapped in the sediment. The study investigates the long-term sinkage behavior of underwater landing robots on seabed sediments using numerical simulations. Focusing on varying pressure source geometries and sediment mechanical properties, this research identifies distinct stages of sediment sinkage: transient, viscoelastic, and stable creep. A time-dependent pressure-sinkage model is established to predict sinkage behavior over extended durations, accounting for the effects of pressure magnitude, pressure source geometry, and sediment characteristics. Results demonstrate significant differences in sinkage depth between cylindrical and plate pressure sources, with maximum disparities reaching 158 mm under high-pressure conditions. The study further reveals that sediment parameters such as density, cohesion, and internal friction angle significantly influence sinkage, particularly in later stages, whereas loading rates affect initial but not long-term sinkage. The findings provide valuable insights for optimizing underwater landing robot designs and operational strategies, especially for long-term seabed deployments on complex sediment types. This research offers guidance for mitigating excessive sinkage risks and improving stability in underwater environments with varied sedimentary conditions.

来源平台：OCEAN ENGINEERING