FILTER BLANKET 

 SEA FLOOR 



Figure 7. Typical toe trench 



underwater features using floating equipment, particularly toe berms, prior to 

 placement of core material, underlayers, and primary armor. The sequence of 

 operations, specific placement techniques, and the associated equipment avail- 

 able to perform this work usually constrain the range of alternate breakwater 

 configurations to some degree. No breakwater configuration should be con- 

 ceived without thorough attention to its method of construction. More de- 

 tailed discussions of these considerations are available in Bruun (1979), 

 Kjelstrup (1979), Maquet (1984), and Bruun (1985). 



Physical Modeling for Stability 



Guiding principles 



42. The specific techniques applied in physical modeling of rubble- 

 mound breakwaters by various hydraulic laboratories differ in detail, but the 

 guiding principles of similitude offer the same basic constraints in all 

 cases. Scale models of breakwaters for hydraulic stability are designed ac- 

 cording to the Froude scaling relation which requires that the Froude number 

 of the model be equal to that of the full-scale prototype in its intended 



27 



