15 stones moved to in front of the toe wall and 18 stones carried over the 

 crest of the dike during Test 46, 9 stones displaced to in front of the toe 

 wall in Test 47, and 3 stones displaced to seaward of the toe wall in 

 Test 49. Displaced stones were not replaced until after Test 49. 



For Tests 50 through 53, the beach elevation in front of the seawall was 

 raised to +14.3 ft mlw. There was no overtopping in Test 50 and only a 

 very small and unmeasurable overtopping from one wave in Test 51. 

 Neither Test 50 nor 51 had any armor stones displaced. Tests 52 and 53 

 had measurable overtopping, with six armor stones displaced seaward and 

 eight armor stones displaced shoreward during Test 52, and two armor 

 stones displaced seaward in Test 53. 



Tests 54 through 57 raised the beach elevation in front of the seawall to 

 + 16.7 ft mlw. Minor overtopping was observed during Tests 54 and 55 

 with two armor stones displaced seaward in Test 54. There was no over- 

 topping and no armor stone displacement in Tests 56 and 57. 



Armor Unit Stability 



Stability of armor units on the rubble-mound dike was not specifically 

 tested, but the following information may be of value for design purposes. 



As reported above, there was no armor stone displacement using stones 

 with an average weight of 0.022 lb and bathymetry from the 1991 survey. 

 Armor stone displacement during tests with the 1978 bathymetry and 

 armor stones averaging 0.011 lb are given in Table 18. Armor stones used 

 in the tests were a crushed dolomite with a unit weight of 165 pcf. Based 

 on relationships defined by Froude's model law (see Chapter 2, "Test Fa- 

 cility"), the following transference equation is derived to determine proto- 

 type stone weights. 



(^a) (L) (L^ 



p p 



where 



L 



P 



(5,) - r' 



e 



(^J - 1 



W^ = weight of an individual stone, lb 

 subscripts m,p = model and prototype values, respectively 

 Ya = specific weight of an individual stone, pcf 

 L^Lp = linear scale of the model 



56 



Chapter 5 Revere Dike Study 



