DHARMLATERAL EARTH PRESSURE AND STABILITY OF RETAINING WALLS 539Questions and Problems
13.1 Write notes on:
(a) Rankine earth pressure theory.
(b) Rebhann’s construction. (S.V.U.—Four year B.Tech.—Sept.,1983,
B.E.(R.R.)—Sep., 1978)
(c) Culmann method. (S.V.U.—Four-year B.Tech.—Dec., 1982)
(d) Coefficient of passive earth pressure. (S.V.U.—B.Tech., (Part-time)—June, 1982)
13.2 (a) Distinguish between ‘active’ and ‘passive’ earth pressure.
(b) Explain clearly Rebhann’s graphical construction method to evaluate the earth pressure on a
retaining wall. What are the advantages or disdvantages of Culmann’s graphical method as
compared to Rebhann’s graphical method? Illustrate your answer by working out an exam-
ple, assuming suitable data. (S.V.U.—B.Tech., (Part-time)—Sept., 1983)
13.3 What are the design criteria to be satisfied for the stability of a gravity retaining wall? Indicate
briefly how you will ensure the same. (S.V.U.—B.Tech., (Part-time)—Sept., 1983)
13.4 Differentiate critically between Rankine and Coulomb theories of earth pressure.
(S.V.U.—Four-year B.Tech.—Apr., 1983, B.E., (R.R.)—Feb., 1976, Nov., 1973)
13.5 Explain (i) active, (ii) passive and (iii) at rest conditions in earth pressure against a retaining
wall. (S.V.U.—Four-year B.Tech.—Dec., 1982, B.E., (Part-time)—Dec., 1981)
13.6 With the aid of Mohr’s circle diagram explain what is means by active and passive Rankine
states in a cohesionless soil with a horizontal surface. Hence obtain an expression for the inten-
sity of active earth pressure behind a vertical wall and explain why for this condition there is an
implied assumption of smooth wall. (S.V.U.—B.E., (R.R.)—Sept., 1978)
13.7 Describe Culmann’s graphical method of finding earth pressure and explain the classical theory
of earth pressure on which this procedure is based. Explain how surcharge will affect earth
pressure in active and passive states. (S.V.U.—B.E., (R.R.)—Nov., 1975)
13.8 Describe the wedge theory for determining active earth pressure and evaluate the assumptions.
Discus the advantages. (S.V.U.—B.E., (R.R.)—May., 1975, Nov., 1974, May, 1971, Nov., 1969)
13.9 Explain Rankine’s theory of earth pressure. For what types of retaining walls and soils may this
theory be used? (S.V.U.—B.E., (R.R.)—May, 1970)
13.10 Indicate an analytical or graphical method to calculate the active earth pressure due to a cohe-
sive soil (c = φ soil) against a rigid retaining well. (S.V.U.—B.E., (R.R.)—May, 1969)
13.11 Derive a general expression for active earth pressure by the wedge theory behind a vertical wall
due to a cohesionless soil with a level surface. (S.V.U.—B.E., (N.R.)—May, 1969)
13.12 A wall with a smooth vertical back and 9 metres high retains a moist cohesionless soil with a
horizontal surface. The soil weighs 15 kN/m^3 and has an angle of internal friction of 30°. Deter-
mine the total earth pressure at rest and its location. If, subsequently, the water table rises to
the ground surface, determine the increase in earth pressure at rest. Assume effective unit weight
of soil as 9 kN/m^3.
13.13 Determine the active and passive earth pressure given the following data: Height of retaining
wall = 10 m; φ = 25°; γd = 17 kN/m^3. Ground water table is at the top of the retaining wall.
(S.V.U.—Four-year B.Tech.—Dec., 1982)
13.14 A retaining wall 12 metres high is proposed to hold sand. The values of void ratio and φ in the
loose state are 0.63 and 30° while they are 0.42 and 40° in the dense state. Assuming the sand to
be dry and that its grain specific gravity is 2.67, compare the values of active and passive earth
pressures in both the loose and dense states.