Table 15. Values of r for one layer of tribars on 1 on 3 

 slope with tribars underlain by two filter layers 

 (after Vanoni and Raichlen, 1966) . 



d s /Hi 



H£/k p 



H^/gT 2 



r 



dg = 0.19 m (0.622 ft) 



3.0 



1.56 



0.00113 

 0.00148 

 0.00201 



0.40 

 0.38 

 0.39 



5.0 



0.94 



0.00068 

 0.00089 



0.39 

 0.38 



Another set of runup tests was conducted by McCartney and Ahrens 

 (1975), using Gobi blocks (Fig. 44) which are used for revetment in 

 low-energy wave climates. The full-size block weighs approximately 

 6.35 kilograms (14 pounds) and is placed in a matlike arrangement on 

 the slope. Tests were conducted with a 4.57-meter water depth, and 

 were limited to a relative depth of dg/H^ = 8.0 and slope of 1 on 3.5. 

 Rough-slope to smooth-slope ratios were r w 0.93, a high value for a 

 roughened slope, but it indicates the relatively smooth surface pre- 

 sented by Gobi blocks. 



Conditions Tested 



d s =4.57m (15 ft) 

 d s /H «8.0 

 H /k r «5.7 

 I on 3.5 slope 

 Horizontal bottom 



0.l0m(3-jf 



in )— , 





A 





[Ml 





r\ 



1 



' t 



kr 



Elevation of Gobi Blocks Plan View of Gobi Blocks 



Figure 44. Gobi blocks (McCartney and Ahrens, 1975). 



93 



