EFFECTIVE METHODS FOR COVERING BREAKWATER RUBBLE MOUNDS AGAINST TSUNAMI USING FILTER UNITS

Abstract

 Rubble mound cover on the harbor-side of a breakwater using filter units is one possible method to reduce construction cost in countermeasures against tsunami. Hydraulic model experiments were conducted to clarify effective layouts of filter units against tsunami overflow. Filter units proved to be more stable than armor stones. A single-layer placement of filter units, partially overlapping enhanced the stability limit compared to without overlapping. Multi-layer placement delayed the progress of damage. Connecting filter units not only enhanced the stability limit, but also slowed progress in damage. Restraint of stone filling movement by connecting the top and bottom of the units improved stability against tsunami overflow.