We made a sensitivity analysis of scour event by changing various environmental parameters using by a mechanical model we have already developed. It was then presumed that the ice condition surrounding the ridge and the bottom shape of the ridge would greatly affect the ice scour event. We also found that the calculation under the assumption that an ice ridge simply moves horizontally during ice scouring (scour curve ζ =0) might not always give the result on basis of safety for the burial depth of embed structures such as pipelines. Also, a simulation method of scour depths, which combined a Neural-network with the mechanical model, was also presented briefly.
Ice-Scour Event is a phenomenon that occurs when ice such as an ice ridge or iceberg comes into contact with seabed. Ice-Scour has been reported to cause damage to communication cables and water intake pipelines. While we have studied the scour-processes by many experiments on ice-scour event including the medium-scale model test, we have also developed the mechanical model (Kioka et al., 2000), which consists of the equation of motion concerning an ice and the simple model of interaction between the seabed and the ice keel. Also, we indirectly validated the mechanical model using the experimental results obtained in small- and medium-scale model tests (Kioka et al., 2001a; 2001b; 2002). Our final goal is to develop the method for estimation of scour depth, or optimal depth of a buried structure such as a pipeline. We believe that we can establish the method by combining the mechanical model and the scour curve, which is a two dimensional locus remaining when ice keel ploughs the seabed. However, we need to establish the scour curve experimentally, which is difficult to be estimated by a theoretical approach.
