DHARM540 GEOTECHNICAL ENGINEERING13.15 A retaining wall with a smooth vertical back, 4.5 m high, retains a dry cohesionless backfill level
with the top of the wall. γ = 18.6 kN/m^3 and φ = 30°. The backfill carries a uniformly distributed
surcharge of 20.6 kN/m^2. Determine the magnitude and point of application of the total active
thrust per lineal metre of the wall.
13.16 A 9 metre high retaining wall retains a soil with the following properties: φ = 36°; γ = 18 kN/m^3.
What will be the increase in horizontal thrust if the soil slopes up from the top of the wall at an
angle of 36° to the horizontal than when it has a horizontal surface?
13.17 A wall with a smooth vertical back 9 m high supports a purely cohesive soil with c = 10 kN/m^2
and γ = 18 kN/m^3. Determine the total Rankine active thrust per metre run, the position of zero
pressure and the distance of the centre of pressure from the base.
13.18 A retaining wall, 4.5 m high, retains a soil with c = 2 N/cm^2 , φ = 30° and g = 20 kN/m^3 , with
horizontal surface level with the top of the wall. The backfill carries a surcharge of 20 kN/m^2.
Compute the total passive earth resistance on the wall and its point of application.
13.19 A R.C. retaining wall holds dry sand fill 6 m in height. The unit weight of sand is 19.3 kN/m^3 and
φ = 32°. Assuming the back of the wall to be vertical, calculate the earth pressure on the wall by
Rebhann’s construction δ = 16°. (S.V.U.—B.E., (R.R.)—Dec., 1968)
13.20 A gravity retaining wall retains 12 m of a backfill. γ = 18 kN/m^3 , φ = 25° and wall friction = 0°.
Using Culmann’s method, determine the active earth thrust. IF the water-table is 6 m from the
top, determine how the earth pressure gets affected. (S.V.U.—Four-year B.Tech.—Apr., 1983)
13.21 A masonry retaining wall of trapezoidal section with the vertical face on the earth side is 1.5 m
wide at the top and 3.5 m wide at the base and is 5.0 m high. It retains a sand fill sloping at 2
horizontal to 1 vertical. The unit weight of sand is 18 kN/m^2 and φ = 30°. Find the maximum and
minimum pressure at the base of the wall assuming the unit weight of masonry as 23 kN/m^3.
(S.V.U.—B.E., (Part-time)—Apr., 1982)