STUDY ON STABILITY OF ‘DRIM’ UNDER WAVES FOR PRACTICAL DESIGN

DRIM (Distorted Ripple Mat) blocks are placed in the flat to works as an unit which controls sediment transport. For practical design of DRIM, it is necessary to examine the stability of both block and unit. In this paper, three series of physical model test are conducted. Firstly, the stability of DRIM is examined and stability number, Ns, is shown. Secondary, both rotation of start block and local scour around the outer perimeter of the unit are key phenomenon to discuss the deformation of DRIM. Finally, it is confirmed that rubble blocks show high performance to increase the stability of both block and unit.