Question

The zero-air voids curve is non-linear owing to

• A. The standard proctor test data of dry density and corresponding water content plotting as a non-linear curve
• B. The dry density at 100% saturation being a non-linear function of the void-ratio
• C. The water content altering during compaction
• D. The soil being compacted with an odd number of blows

Answer 1

The correct option is B The dry density at 100% saturation being a non-linear function of the void-ratio

Dry density,

${\gamma }_d=\frac{(1-n_a)G_{{\gamma }_w}}{1+Gw}$

For zero air void density

$n_a=0$ and S = 1

$({\gamma }_d{)}_{theoretical}=\frac{G_{{\gamma }_w}}{1+Gw}$ ...(i)

We know that,,

eS = Gw

e = Gw

From (i)

$({\gamma }_d{)}_{theoretical}=\frac{G_{{\gamma }_w}}{1+e}$

Thus, dry density at 100% saturation being a non-linear function of void ratio and water content.

Hence the zero-air voids curve is non linear.