where F_ = long-term static holding capacity 



A = projected fluke area 



B = fluke width or diameter 



L = fluke length or diameter 



c 1 = soil cohesion intercept 



y = soil buoyant unit weight 



D = fluke depth below soil surface 



N 1 = long-term holding capacity factor in cohesive soil 



N = holding capacity factor for drained or frictional 

 q condition 



The prediction of long-term holding capacity is based on the principle 

 that the behavior of cohesive and cohesionless soils is basically the 

 same. Hence, in cohesive soils with full drainage, the effective stress 

 principle can be applied using the drained strength parameters <j> and 

 c'. The N' 's (Figure 5-3) to be applied to the cohesion are different 

 than the N 's applied to the undrained shear strength when predicting 

 short-term holding capacity. For short-term loading, the holding 

 capacity factors include the effect of suction below the anchor fluke. 

 The factors to be used here do not include it, because, for long-term 

 use, suction below the anchor is dissipated. The values of N are 

 presented in Figure 5-2 and are the same as those for analyzing short- 

 term loading in cohesionless soils . 



When the soil is loose (soft), the shear failure of the soil is dif- 

 ferent than when the soil is firm. To account for this difference, 

 drained strength parameters, <j> and c', should be reduced by one-third 

 before selecting holding capacity factors as is done in bearing capacity 

 analyses. For $, the reduction is applied to the tangent of $, and then 

 a revised <|> is obtained by determining the arc tangent of the result. 



45 



