Abstract: Based on the Zhujiajian landslide in Zhoushan Islands, this paper developed a large-scale water tank-like physical model test device for investigating the influence of waves on the instability and failure of offshore submarine slopes, and built a wave division multiplexing technology-based fiber inspection system. The model test of the offshore submarine landslide under the action of waves was carried out, the variation law of pore water pressure and displacement in the slope model caused by waves was revealed, and the variation law of the surface velocity of the slope model was analyzed. Based on the SPH numerical simulation, the research on the sliding accumulation characteristics of the submarine slope under the action of waves was carried out to understand the catastrophic evolution process of the submarine landslide. Results showed that under the continuous action of waves, the bottom of the submarine slope was the first to be damaged, and then the slope became unstable and was damaged with the time elapsed. When a submarine landslide occurred, the displacement in the middle location of the slope and below changed abruptly, while the slip distance at the top of the slope was relatively small; waves affected the displacement and pore water pressure of the submarine slope simultaneously. When the slope was destabilized and damaged, the slope displacement and the pore water pressure changed suddenly, but the time of the sudden change of pore water pressure was slightly earlier than that of the displacement. Meanwhile, based on the landslide simulation of Zhujiajian geological profile I, the sliding accumulation characteristics of Zhujiajian offshore submarine landslides were preliminarily obtained. A set of test techniques and methods suitable for offshore submarine landslides under the action of waves has been established, which provides important guiding significance and reference values for the field research of offshore submarine landslides.

Key words: submarine landslide, model test, wave action, stability analysis