Calculating the increase in stress to the top of the clay layer, use H 10 m
a rH 1410 1.4
Entering the upper part of Fig. 4.16 with k 10, extrapolating between the a 1 and a 2
curves, the value of (I)(Hr)2 0.24
I (0.24)(Hr)2 (0.24)(1014)2 0.47
sz v Ip (0.47)(50 kPa) 23 kPa
The stress increase of 23 kPa is only applicable at the top of the clay layer. However, using this
value for the center of the clay layer and since OCR 1, from Eq. 8.12:
sc Cc [Ho (1 eo )] log [(s′vo v)s′vo]
sc (0.83)[(2 m)(1 1.1)] log [(150 kPa 23 kPa)150 kPa] 0.049 m 4.9 cm