a - Cohesive Soils . The force required to embed the deadweight 

 skirts, f) e , is to be evaluated usinq the relationship 



1 e = sN c A + s f A s (19) 



where s = undrained shear strenqth at the cuttinq edge tip, (Pa) 



N = bearina capacity factor taken to be 9 for cuttinq edqes 

 L of Z/t = 5 



A = bearing area of the cuttinq edge tiDS (m ) 



s f = mobilized soil /cutting edge wall friction (Pa) 



A = side area of the cuttinn edge (m ) 



Unfortunately, during the cutting edge embedment analysis, the bearina 

 caoacity term of Equation (19), i.e., the term sN A, was improperly eval- 

 uated yieldina values of force reauired to embed the cuttinq edges, , 

 about 5 Dercent too hiah. The error is on the conservative side indicating 

 a qreater deadweiqht reauired than is really necessary to acfcomnlish embedment 



b. Mon-Cohesive Soils . The force reauired to embed the deadweight 

 skirts in non-cohesive soils (sand-like) is to be evaluated using 

 the relationship 



= A(l/2 ytNydy + ZN s d ) + A Ka tan 4> (20) 



e q a a' s v 



where t = thickness of cuttina edge (m) 



Ny and N = bearing caoacity factors (see Fiqure 40 of CEL TM-42-76-1 , 

 a Valent et al . , 1976) 



s = shane factor = 1 + tan <J> 



q 



d = factor to account for the shearing resistance of soil above 

 q the bearing plane of the anchor 



- 1 + 2 tan 4.(1 - sin "$) 2 tan _1 (Z/t) (21) 



d Y - (purpose same as d ) = 1 + 0.* tan _1 (Z/t) (22) 



K = coefficient of lateral pressure on cutting edqe wall 



a = vertical effective stress (Pa) 

 v 



91 



