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Two soils were tested for their consistency limits in the laboratory. The following data were obtained

plasticity of soil • 295  views
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From fig the flow curves for soil A and soil B

From the fig $(w_{L})_{A}$=38%

$(wl)_{B}$=60%

a) $(Ip)_{A}$=38-25=13

$(Ip)_{B}$=60-30=30

soil B has a higher degree of plasticity soils with $IP \gt 17$ are highly plastic and soils with Ip between 7 and 17 are "medium plastic", according to one empirical classification system

b) $(IL)_{A}$=$\frac{W_{N}-W_{P}}{IP}$ = $\frac{40-25}{13}$

$(IL)_{B}=\frac{50-30}{30}$=0.67

soil A with $I_{2}\gt 1$ is in the liquid state of consistency and will, therefore 'flow' like a viscous clurry upon remoulding. soil B with $I_{2}$=0.67 is in the plastic state and will be a better foundation material upon remoulding.

c)soil with WL=60% is more compressible than soil A with wL=38% compressibility is a direct function of the liquid limit

d) From fig, Flow Index, If of soil A=42.0-32.0=10 (Considering water content at 10 and 100 blows) If for soil B=6.26-55.5=71

Since $(IF)/A \gt (If)_{B}$ soil A showed greater loss if shear strength with increase in water content

e) Toughness Index, $I_{t}$ for soil A=$\frac{IP}{IF}=\frac{13}{10}$=1.3

If for soil B=$\frac{Ip}{If}=\frac{30}{71}$=4.22

soil B has a higher shear strength at plastic limit since a soil with higher toughness index possess higher shear strength at plastic limit

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