Question

What is the correct expression of equivalent liquid unit weight?

(a) ϒeq.tan^2 [45 – Φ/2]

(b) ϒeq.tan^2 [45 + Φ/2]

(c) ϒeq.tan [45 – Φ/2]

(d) ϒeq.tan [45 + Φ/2]

This question was posed to me in homework.

I would like to ask this question from Stability of Earthen Slopes topic in portion Earthen and Rock Fill Dams of Irrigation Engineering

Answer 1

The correct answer is (a) ϒeq.tan^2 [45 – Φ/2]

Best explanation: This term is used in the analysis of the stability of the foundation against shear. It is based on the assumption that soil has an equivalent liquid unit weight which would produce the same shear stress as the soil itself.

ϒeq.tan^2 [45 – Φ/2]

where ϒeq = the equivalent unit weight of dry soil in foundation and dam and Φ = the equivalent angle of internal friction.