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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165<br />
Similarly, soil thicknesses <strong>of</strong> black <strong>clays</strong> with depths equal to <strong>an</strong>d/ or greater th<strong>an</strong> 0,50m show<br />
linear shrinkage values generally concentrated about 25% (Figure 8.7b); with percentage<br />
values <strong>of</strong> 23-26, 21-26, 24-29, 25-27 <strong>an</strong>d 25-26 recorded for pr<strong>of</strong>iles A, B, C, D <strong>an</strong>d E,<br />
respectively. On the whole across the study area, values <strong>of</strong> 21-29% exhibiting a r<strong>an</strong>ge <strong>of</strong> 8%<br />
as well as a mode, medi<strong>an</strong> <strong>an</strong>d me<strong>an</strong> <strong>of</strong> 25% have been recorded for the depth. A st<strong>an</strong>dard<br />
deviation <strong>of</strong> 1,29 <strong>an</strong>d vari<strong>an</strong>ce <strong>of</strong> 1,67, have also been calculated. Fig. (8.8) shows a<br />
contoured distribution pattern <strong>of</strong> linear shrinkage at the two depth intervals.<br />
Linear shrinkage (LS) variation (< 0,5 m)<br />
2527 25 24 26<br />
1°19´S 4000<br />
Pr<strong>of</strong>ile dist<strong>an</strong>ce (m)<br />
26 26 27 24 25 27 27 26<br />
3000<br />
23 23 24 23 24 24 26<br />
2000<br />
West<br />
23 24 24 25 25 24 25<br />
1000<br />
23 23 24 25 25 25 25 29<br />
1°21.5´S 0<br />
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000<br />
36°49´E<br />
South<br />
Pr<strong>of</strong>ile dist<strong>an</strong>ce (m) 36°55´E<br />
LS (%)<br />
27.5<br />
27<br />
26.5<br />
26<br />
25.5<br />
25<br />
24.5<br />
24<br />
23.5<br />
23<br />
Linear shrinkage (LS) variation (> 0,5 m)<br />
2326 25 26 24<br />
1°19´S 4000<br />
22.5<br />
Pr<strong>of</strong>ile dist<strong>an</strong>ce (m)<br />
27 27 26 25 25 26 25 26<br />
3000<br />
25 25 25 21 25 25 25<br />
2000<br />
West 25 26 25 26 26 25 26<br />
1000<br />
1°21.5´S<br />
24 24 24 24 25 26 26 29<br />
0<br />
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000<br />
36°49´E<br />
South Pr<strong>of</strong>ile dist<strong>an</strong>ce (m) 36°55´E<br />
27<br />
26.5<br />
26<br />
25.5<br />
25<br />
24.5<br />
24<br />
23.5<br />
23<br />
22.5<br />
22<br />
Figure 8.8. A contoured distribution pattern <strong>of</strong> linear shrinkage in black <strong>clays</strong>.<br />
27.5<br />
LS (%)<br />
A comparison <strong>of</strong> linear shrinkage values <strong>of</strong> black <strong>clays</strong> for depths <strong>of</strong> less th<strong>an</strong> 0,50m with<br />
those obtained for depths equal to/ <strong>an</strong>d greater th<strong>an</strong> 0,50m yield a moderately strong<br />
correlation <strong>of</strong> 0,61 <strong>an</strong>d a covari<strong>an</strong>ce <strong>of</strong> 1,05. In addition, there is a strong agreement between<br />
values <strong>of</strong> linear shrinkage obtained for the two depth intervals in terms <strong>of</strong> comparable<br />
respective parameters <strong>of</strong> mode, medi<strong>an</strong>, me<strong>an</strong>, st<strong>an</strong>dard deviation <strong>an</strong>d vari<strong>an</strong>ce. This serves to