Tsunami Scour Mechanisms Around a Cylinder

The scouring mechanism due to tsunami run-up around a vertical cylinder was investigated experimentally using a large-scale tsunami experimental facility. A variety of solitary waves were generated and allowed to run up onto a uniformly sloping sandy beach. The scouring process around the cylinder on the beach was optically recorded using CCD video cameras installed inside of the cylinder. In addition, the water-surface elevation, flow velocity, and pore pressure around the cylinder were measured with electronic sensors. We surveyed the topographic changes before and after the run-up. It was found that the pore-pressure field around the cylinder is the key factor in understanding tsunami scouring mechanism.