PART III: TEST RESULTS 



19. Various combinations of wave height and period and water depth were 

 investigated for the selected armor weights and structure slopes. Some of 

 these conditions proved to be too severe, i.e., they produced excessive damage 

 as measured by the sounding method. Conversely, some conditions proved to be 

 conservative. Results of those tests which yielded stable design conditions 

 are summarized in Table 1. Presented therein are experimentally determined 

 design wave heights and calculated stability coefficients K 's as functions 

 of relative depth d/L and relative wave heights H/d . The stability coef- 

 ficient IC is determined from the Hudson formula, i.e.. 



vh' 



w = 



K /S^ - n' cot a 



where 



K = stability coefficient 



S = specific gravity of armor unit 

 a = reciprocal of breakwater slope 

 Armor units were placed randomly in two layers, and the number of armor units 

 per given surface area was equal to that presently recommended for new con- 

 struction in EM 1110-2-2904 (Headquarters, Department of the Army 1986). 

 Photos 5-11 show typical after-testing conditions of the structures. 



20. Figures 2 and 3 present IC as a function of d/L , H/d , and 

 sea-side structure slope. These data show the stability coefficient to be 

 independent of sea-side structure slope; however, a slight dependency on both 

 d/L and H/d is observed with minimum stability occurring at the lower 

 values of d/L and higher values of H/d , i.e. longer wave periods in shal- 

 lower water. 



21. The minimum stability coefficient (20) observed in the present in- 

 vestigation is very significant. Previous tests of dolos overlays for exist- 

 ing stone armor (Carver and Wright 1988a) and existing dolosse (Carver and 

 Wright 1988b) yielded minimum stability coefficients of 12 and 15. Thus, the 

 obtained value of 20 significantly exceeds that observed for other dissimilar 

 armor combinations and present recommendations for new construction (K_ = 15) . 



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