only recently been adapted to breakwater design, and very little data exist to support 

 prediction of rubble-mound deterioration. Despite the many hundreds, and perhaps 

 thousands, of studies on breakwater armor stability, there have been few generalized 

 studies of long-term deterioration of traditional rubble-mound armor layers. Moreover, 

 there have been no generalized studies of deterioration due to variations in storm 

 sequences using random waves. Finally, damage experiments to date have been 

 primarily conducted with nonbreaking waves, which is atypical of many envirormients 

 in which breakwaters are constructed. 



The purpose of this study was to first identify the primary mechanisms of 

 stone instability and damage development when the breakwater armor layer is exposed 

 to depth limited, breaking waves. Chapter 2 discusses initiation of stone movement. A 

 relation for predicting the initiation of stone movement when exposed to vertical uplift 

 of normally-incident plunging breaking waves is presented in Chapter 2. The equation 

 is verified using data from a small-scale two-dimensional flume physical model study. 

 This portion of the research effort qualitatively addresses incipient motion of stone 

 armor. This section includes the traditional development of a stabihty prediction 

 equation and some insight into the effect of wave steepness on instability. 



A primary goal of this study was to establish predictive relations for damage 

 development on traditional breakwater sections for single storms and for storm 

 sequences given depth-limited normally-incident waves. Chapter 3 introduces the 

 subject with a discussion of historical stability and damage development physical model 



4 



