Experimental study of stability coefficient of breakwater armor layer depending on placement methods

rubble mound breakwater;placement method;Tetrapod;Rakuna-IV;Dimple;Grasp-R;stability coefficient;624

공과대학 건설환경공학부 ;

University:서울대학교 대학원

关键词: rubble mound breakwater;    placement method;    Tetrapod;    Rakuna-IV;    Dimple;    Grasp-R;    stability coefficient;    624;   

Others  :  http://s-space.snu.ac.kr/bitstream/10371/124276/1/000000024892.pdf

美国|英语

来源: Seoul National University Open Repository

【 摘 要 】

The rubble mound breakwater is widely used in Korea as well as throughout the world since its construction technology has been developed through extensive experience for a long time. The armor units used to protect the rubble mound breakwater from severe erosion are made of large stones or concrete blocks which are strong and heavy enough so that they are not broken or displaced by the incident waves. For stable and economic design of a breakwater, many studies have been performed for estimating appropriate weight of the armor units. In 1959, Hudson proposed a formula which includes the stability coefficient. The stability coefficients of various armor units including the Tetrapod are given in the Shore Protection Manual published by U.S. Army Corps of Engineers in 1984. However, their applicability is limited because they were developed based on regular wave experiments and only random placement was used for the concrete armor units.In this study, we propose different placement methods of concrete armor units on a rubble mound breakwater and determine the corresponding stability coefficients. The investigated armor units include the Tetrapod, which is the most widely used in Korea, Rakuna-IV, Dimple, and Grasp-R. The slope of the breakwater is fixed as 1:1.5, which is the most commonly used for rubble mound breakwaters. Regular placement methods are proposed, which are more frequently used in Korea than random placement methods. The stability coefficients are proposed based on the Hudson’s formula for different placement methods of each armor unit. Two different placement methods are proposed for Tetrapod and Rakuna-IV, giving similar stability coefficients regardless of the placement method. Dimple is also experimented with two different placement methods whose results show somewhat different stability coefficients. Finally, Grasp-R is experimented with one placement method which results in a larger stability coefficient compared to other armor units.