Deeper Water Test Results (d = 1.60 ft) 



Test results for the 0.80-ft depth showed the lower stabilities consis- 

 tently occurred at the higher values of gamma; therefore, tests at the 1.60- 

 ft depth (Table 2) were conducted using gamma values of 10 and 20 only. 

 Figure 10 presents Kj^ as a function of gamma for all wave periods and 

 Figures 11-14 present results for constant wave period. Figure 15 pre- 

 sents stability as a function of grouping intensity. As with the 0.80-ft 

 depth, the lower stabilities are again observed for the longer wave periods 

 and the higher values of gamma and grouping intensity. 



Summary and Nondimensionalization 



Stability is presented as a function of grouping intensity for both water 

 depths in Figure 16. These data show a decrease in stability with increas- 

 ing T and GI; however, no strong depth-dependent trend is evident. Test 

 results are nondimensionalized in Figures 17-19. Presented therein are 

 the stability coefficients as a function of relative depth (d/L) for the two 

 depths individually and collectively. These data show the influence of 

 wave period with the lower stabilities occurring at the lower values of 

 d/L, i.e., longer wave periods in shallower water. As discussed pre- 

 viously, a group of waves is defined as three or more successive waves 

 which have heights equal to or exceeding the significant wave height of 

 the entire test run. The maximum number of waves observed in a group 

 was six. 



Discussion 



Results of this study show stability to be influenced by wave period, 

 spectral width, and wave grouping intensity. As would be expected, the 

 lowest stabilities are observed for the longest wave periods and the most 

 highly grouped waves. Minimum stability coefficients observed herein 

 (values of 0.8, 1.1, 1.6, and 1.8) are especially significant in that they are 

 less than the minimums presently recommended for design (Shore Protec- 

 tion Manual 1984). The levels of wave grouping tested herein are achiev- 

 able at some, but not all, prototype locations; therefore, these results 

 should be applied on a case-by-case basis. 



Chapter 2 Tests and Results 



