RUBBLE TOE PROTECTION 

 8 = 0.4 d s 



RUBBLE AS TOE PROTECTION 



(AFTER BREBNER AND DONNELLY 1962) 



RUBBLE FOUNDATION 

 B = 0.4 d s 



RUBBLE AS FOUND A TION 



(AFTER BREBNER AND DONNELLY 1962) 



DEPTH RATIO 



TWO LA YER ARMOR STONE 

 TOE BERM FOR EXPOSED SIDES 

 OF RUBBLE-MOUND BREAKWATERS 

 AND JETTIES (CERC 1986) 

 0B B = 3t FOR (Wjq) BERM 



WHERE t=(W 50 /7) ,/3 



NOTE: N s VALUES FOR TOE BERMS FRONTING RUB8LE-MOUNO STRUCTURES 

 ARE FOR BREAKING WAVE DESIGN CONDITIONS. 



Figure 12. Stability number cubed versus relative berm depth for toe berms 

 fronting rubble -mound structures and rubble toes and foundations for 

 impermeable vertical structures (after Markle (1989)) 



32 



