Appendix B 



ANCHOR HOLDING CAPACITY 



by R. J. Taylor 



The static pullout resistance of an embedded anchor-projectile 

 may be calculated in various ways depending upon the soil type and 

 anchor configuration. 



Cohesionless Soil 



One method for sands is based upon Vesic's (1969) analysis of 

 the problem of the expansion of a spherical cavity close to the 

 surface of a semi-infinite plastic solid. Vesic's theoretical analysis 

 was chosen because it showed good agreement with results of model tests 

 on loose to medium dense sand which would be typical of ocean depositions, 

 Vesic's theoretical solution gives the ultimate radial pressure needed 

 to break out a spherical cavity below the surface of a solid. The 

 relationship is as follows : 



q = cN + y DN (B-l) 



o c b q 



where q = radial pressure 

 o 



c = soil cohesion 



N = F 

 c c 



N = F +1/2 D/B 



q q 



F ,F = cavity breakout factors 

 c q 



Y, = buoyant unit weight of the soil 

 b 



D = embedment depth 



B = circular plate diameter 



35 



