PHYSICAL MODELING OF RUBBLE MOUND BREAKWATER DEFORMATION ON SOFT SEABED

Soft seabed in some coastal areas causes noticeable problems in the course of construction of marine structures such as rubble mound breakwaters. Pouring rubbles for constructing this type of breakwaters, rock particles sink into the soft soil and a foundation for the breakwater cannot be developed [1] causing excessive settlement, instability of breakwater and waste of materials. Except that the individual penetration of rock particles into the soft soil, other phenomena such as immediate deformation and consolidation of the seabed, flow of soft material into pores of rock fill and erosion of the seabed effect the total waste of rock material [2]. Before choosing the best technique to encounter the problem, it is essential to make an accurate estimation of breakwater deformation and volume loss. There are numerous projects that underestimating the rock material volume required for construction lead to lack of resources, contracting problems, funding difficulties and at least delay in construction process because of need for redesign and change the approach. On the other hand, overestimating the volume loss can lead the project to an expensive improvement technique. In this paper at the first step, data gathering from several projects with considerable waste of rock material was carried out and as case histories took into account. Then, a 1g physical modeling test procedure was suggested for a more detailed study on the subject.