ABSTRACT
Settlement Calculation from e-Iog P Curve for Overconsolidated Clay Soil Fig. 7.9(b) gives the field curve Kf for preconsolidated clay soil. The settlement calculation depends upon the excess foundation pressure I1p over and above the existing overburden pressure Po'
Settlement Computation, if Po + ap S Pc (Fig. 7.9(b)} In such a case, use the sloping line AB. If C
s =slope of this line (also called the swell index), we
have
By substituting for l1e in Eq. (7.8), we have
(7.14a)
(7.14b)
(7.15a)
(7.15b)P Po +l1pl1e = l1el + l1e2 = Cs log-C + Cc log~-- Po Pc
In this case the slope of both the lines AB and BC in Fig. 7.9(b) are required to be considered. Now the equation for St may be written as [from Eq. (7.8) and Eq. (7.15b)]
S CsH I Pc CcH I Po +l1pt =-- og-+-- og~-- 1+ eo Po 1+ eo Pc
The swell index C s
~ 1/5 to 1/10 C c
can be used as a check. Nagaraj and Murthy (1985) have proposed the following equation for C
s as
Cs =0.0461~JGs1100 where wi =liquid limit, G
s =specific gravity of solids.
