an engineering geological characterisation of tropical clays - GBV
an engineering geological characterisation of tropical clays - GBV
an engineering geological characterisation of tropical clays - GBV
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203<br />
PI = 1,88*LS<br />
A comparison <strong>of</strong> plasticity index values calculated using the above relationship (PILS) with<br />
those actually measured in the laboratory (PImeasured) has shown <strong>an</strong>d confirmed a strong<br />
agreement in the two sets <strong>of</strong> data in the form <strong>of</strong><br />
PImeasured = 1,005PILS<br />
The plasticity index <strong>of</strong> red soils could also be estimated from laboratory measured linear<br />
shrinkage using a new relationship developed for the soils, i.e.<br />
PI = 1,84LS<br />
The so calculated <strong>an</strong>d/ or estimated plasticity indices have also been found to be practically<br />
identical to actual laboratory measured values, i.e.<br />
PImeasured = 1,00PILS<br />
Another new relationship has been developed for the estimation <strong>of</strong> plasticity index (PI) <strong>of</strong><br />
black <strong>an</strong>d red soils from laboratory measured values <strong>of</strong> liquid limit (LL) with a high degree <strong>of</strong><br />
approximation, i.e.<br />
PI = 0,79(LL-25)<br />
The so calculated <strong>an</strong>d laboratory measured plasticity indices have been found to be in near<br />
perfect agreement, i.e.<br />
PImeasured = 0,99PILL<br />
Linear shrinkage values could also be estimated by calculation from laboratory determined<br />
liquid limits <strong>of</strong> black <strong>clays</strong> <strong>an</strong>d red soils using the newly developed relationship below, i.e.<br />
LS = 0,39(LL-21)<br />
The calculated <strong>an</strong>d laboratory measured linear shrinkage values have been found to be in very<br />
strong agreement, i.e.<br />
LSmeasured = 0,997LSLL<br />
The swelling capability <strong>of</strong> black <strong>clays</strong> <strong>an</strong>d red soils, in terms <strong>of</strong> free swell (FS), could be<br />
estimated with a high degree <strong>of</strong> approximation by calculation from laboratory determined<br />
Atterberg limits (LL, PI) <strong>an</strong>d linear shrinkage (LS). The new derived relationships take the<br />
form <strong>of</strong><br />
FS = 3,17(LL-45),<br />
FS = 3,79(PI-13) <strong>an</strong>d<br />
FS = 7,29(LS-7)