Question

At time t, the hydraulic head corresponding to excess hydrostatic pressure is __________

(a) \(h=\frac{σ’}{γ_w}\)

(b) \(h=\frac{\overline{u}}{γ_w} \)

(c) \(h=\frac{γ_w}{\overline{u}}\)

(d) \(h=\frac{σ’\overline{u}}{γ_w} \)

This question was posed to me in an internship interview.

Enquiry is from Terzaghi’s Theory of One Dimensional Consolidation in division One Dimensional Consolidation of Geotechnical Engineering I

Answer 1

Correct answer is (b) \(h=\frac{\overline{u}}{γ_w} \)

Easiest explanation: The excess pore pressure in terms of its head is given by,

u=hγw

therefore, on rearranging the equation,

the hydraulic head corresponding to excess hydrostatic pressure is,

\(h=\frac{\overline{u}}{γ_w}.\)