Stability coefficients of Tetrapod, Rakuna-IV and Dimple depending on placement methods

摘要

In this study, two different uniform placement methods are proposedfor each of Tetrapod, Rakuna-IV, and Dimple armoring a rubble moundbreakwater and the corresponding stability coefficients are determinedby hydraulic experiments. The Tetrapod and Rakuna-IV show similarstability coefficients regardless of the placement methods, whereas theDimple shows somewhat different stability coefficients depending onthe placement methods. It is shown that the Dimple gives the largeststability coefficient, whereas the Tatrapod gives the smallest value. Theuniform placement methods of Tatrapod and Rakuna-IV give slightlylarger stability coefficients than the random placement, whereas theuniform placements of Dimple give much larger stability coefficientsthan the random placement. However, the small void ratio of uniformplacements of Dimple requires attention because the blocks wouldbehave like single layer system blocks so that brittle failure couldoccur.