Table 4.1 



Experimental Conditions for Initial Damage Experiment 



Parameter 



Range || 



Water depth at toe, h, 



11.9 -15.8 cm 



Wave height at toe 



Variable 



Peak wave period, Tp 



2.48 - 2.59 sec 



Seaward beach slope, cot a 



20 



Structure slope, cot 6 



2 



Structure crest height above bottom, h^ 



30.5 cm 



Nominal armor stone diameter, D^o 



3.64 cm 



Median armor stone mass, Afgg 



128 g 



Stone density, p^ 



2.66 g/cm^ 



Afjo = 128 g, while the underlayer was sieve sized passing 1.59-cm and retained on 

 1 .27-cm sieves. The ratio of armor median mass to underlayer median mass was 

 (Mso)^ / (M5o)„ = 25, which was large relative to that typically used in the prototype. The 

 gradation of the armor layer for this initial series was very narrow with D^^ID^^ = 1.05, 

 where Dgj is the nominal diameter corresponding to the 85-percent exceedance 

 probability in stone mass and D^^ is the nominal stone diameter corresponding to the 15- 

 percent exceedance probability. The gradation of the underlayer was wider with 

 Dgs/Dij = 1 .44. The core material was sieve sized, passing No. 3 (0.67-cm) and retained 

 on No. 4 (0.47-cm) sieves. While not impermeable, this core material was sized small 

 enough to prevent strong flow within the core. Equations 3.7 and 3.8 indicate that lower 

 porosity in the underlayer and core results in lower stability. Therefore, the underlayer 



57 



