= 6K'(S + y + H' 



1 + 0.2 



D 



+ STs 



(12) 



In addition to being the bearing capacity equation for a plate which 

 has settled an amount S, the above may also be interpreted as a pressure- 

 settlement formula for pressures in excess of the surface bearing capacity 

 (that is, the bearing capacity for S = 0). For example, if the soil and plate 

 parameters 7^, H', K', and D are known and if a settlement S greater than 

 zero is assumed, then a value of p may be obtained from Equation 12. If 

 this pressure is applied to the plate at the surface, the bearing capacity will 

 be exceeded and the plate will begin to settle. When it has settled an amount 

 S, the pressure will just equal the bearing capacity and equilibrium will be 

 established. Equation 12, therefore, can be used to predict settlements for 

 relatively large bearing pressures. 



Comparison of Solutions 



A specific example was chosen for the purpose of comparing the 

 elastic and bearing capacity solutions. The settlements corresponding to 

 the 0. 125-tsf bearing pressure level were obtained from the Series III average 



results; and the quantity p/S, derived 

 from these results, was plotted versus 

 the plate size D in Figure 19. 



Predictions of p/S for this 

 situation, obtained using both the 

 elastic and bearing capacity solu- 

 tions, are also presented in Figure 19. 

 The bearing capacity values were cal- 

 culated according to Equation 12 

 using the soil parameters derived 

 from a least squares fit of the vane 

 shear strength data of Figure 9. The 

 elastic predictions including confi- 

 dence limits were obtained from 

 Equations 8 and 9 using Figure 18 

 for the expected value and 95% 

 2.0 confidence limits of A(p). 



As may be seen from Figure 19, 

 both the expected settlements predicted 

 by the elastic solution and the settle- 

 ments predicted by the bearing capacity 

 solution closely approximate the 



0.2 



'\. 



•^" 



°~^^^^ 



c:^^^ 



n 1 









=:;i:::::rr 



r,:::.™,„, 



1.0 



D (feet) 



Figure 19. Comparison of experimental 

 data with elastic and bearing 

 capacity solutions (Series III, 

 p = 0.125 tsf). 



25 



