The Influence of Slopes to the Stability of Stones in front of Seawall

Abstract

Seawall is a coastal protection structure to prevent coastal erosion from wave forces. In this research, rubble-mound of stones are used as armor due to the availability of the material in coastal areas and ease of construction. A series of physical model tests with a scale of 1:25 with a variation of four wave heights (H), two wave periods (T), and three different slopes of rubblemound in front of seawall were performed. Parameters used in the research are stability coefficient (KD),wave steepness (H/gT ), and percentage of damages (Do). The slope variations of rubblemound were 1:1.15, 1:1.5, and 1:2. The experiments also displayed that the stone stability coefficient (KD) directly proportional with wave steepness (H/gT). The value of KD for the seawall model with the slope angle of cot = 1.15 is 4.4, cot = 1.5 is 4.28 and cot = 2 is 3.02. From all three variations of slope, the most stable is on the slope 1:2 with the least damage impact on the model. The gentlest slope is the most stable structure.