Discrete element analysis of torpedo anchor penetration into calcareous sands considering particle breakage

As a new type of deep-sea anchorage device, the torpedo anchor is widely used in deep-sea oil and gas exploitation projects, but few attentions have been paid to the torpedo anchor penetrating into coral deposits. Based on the discrete element method, the penetration process of torpedo anchor into calcareous sands is numerically analyzed. The reliability of the numerical model is verified by comparing with the existing indoor test results. The numerical simulation focuses on the evolution of particle breakage of soils around the anchor during the penetration process, and its macro and micro effects on the anchor penetration characteristics are also discussed. The results show that in the process of torpedo anchor penetration, the soil around the anchor tip is seriously broken, while the particle breakage at the anchor side is relatively weak. The particle breakage quantity increases with the increase of penetration depth, and the distribution of particle velocity field is basically symmetrical along the central axis of the anchor body. With the increase of penetration depth, the distribution range of particle velocity field expands, and the peak particle velocity first increases and then decreases during the penetration process. The peak value in the stress concentration area first increases and then decreases, when the penetration depth increases. After the flange starts to contact the soil, the stress within the soil reaches the maximum. The research results can provide references for the design of dynamic anchor penetration in island and reef engineering.