바이오블록개발과 해저식생조성을 위한 현장적용해석

Abstract

In order to protect coastal facilities mainly from wave and current actions, the self-locking bio blocks constituting component elements of protecting structures against scouring were designed. These blocks are adapted to the sloping bottom, coastal dunes, and submerged coastal base counteracting the destructive and erosive impulse action. The developed bio block technology will enable an eco-friendly rehabilitation alternative for creation of marine vegetation near coastal area. A series of laboratory experiments is necessary to investigate the reflection of water waves over and against a train of protruded or submerged shore structures and compare the reflecting capabilities of incident waves including wave forces. In this study the hydraulic model experiment was conducted to identify the performance of newly designed water affinity bio blocks to keep the coast slope and bottom mound from scouring by reduction of the reflection coefficient and to convince stability of the placements. Revised design of each element of blocks were also tested for field conditions. In general about 33% reduction effect on reflection rate of bio block slope was achieved at the final design hydraulic experiment. Although partial displacements appeared at the foot blocks from the block stability experiment with the available wave conditions, it might be soluble by replacing them with the mid-hole blocks and piling and enhancing the unit block weight in field. From the result of lab experiment, the field applicability of the developed blocks and placement was conducted at the field test bed and monitored that. In order to place the real blocks, numerical analysis of wave climate for the test bed was made and selected the site based on the result. The species of vegetation for test bed is the eel grass. Site survey for eel grass vegetation was done at Yeongdo coastal sea, together with other sites such as Yeongil Bay.

It is expected to use the developed blocks as a hard method to control directly the applied forces by reduction and scattering of wave forces on the laid pipelines near coastal waters or at the eroding area. And it might contribute to the coastline erosion protection and bottom stabilization by control of landward wave forces and bottom flow with the use of blocks as the armor units of artificial reefs at the surfer zone. The continuation of the present work such as the wave force analysis on the different bio block arrangement and experiments with respect to wave direction is recommended. The restored ecosystem will provide a higher productivity for fisheries resources. It is also expected to commercialize coastal control and beach restoration technologies based on stable placement of the artificial unit blocks in the eel-grass field and contribute to expand the technologies to other related industries. Successful joint research with the highly experienced group is encouraged for coral raising and other marine vegetation on this block under different wave and temperature conditions.