Chapter 1 

 INTRODUCTION 



This thesis addresses the stability of coastal rubble mound stone armor 

 layers exposed to water waves. The most common coastal rubble mounds are 

 breakwaters, jetties, and revetments. Breakwaters usually have a large part of their 

 length oriented peipendicular to the direction of wave travel and their primary purpose 

 is to produce a quiescent area in their lee for ship anchorage or beach sheltering. Jetties 

 are usually oriented parallel to the direction of wave travel and are used to produce an 

 artificial channel or inlet. This channel is usually an entrance to a harbor and is used for 

 commercial or leisure water-craft navigation. Revetments typically armor coastal or 

 riverside slopes that would otherwise erode when exposed to water waves. These waves 

 could be a result of local or distant storms or they could be due to ship wakes. 



Breakwater failure can occur due to a number of different failure modes. 

 The dominant failure modes are shown in Figure 1. Of these, seaside armor stability on 

 a traditional rubble mound is critical to the integrity and fimctionality of breakwaters 

 and is therefore the focus of the present study. Breakwater stone-armor layer stability is 

 unique from other structural design in that it is highly variable, and this variability is 



