QUESTIONS CARRY 2 MARKS EACH
Water is flowing at the rate of 0.2 cc/sec in an upward direc-tion through a sand sample with k = 1 × 10–3cm/sec. Thick-ness of sand sample is 10m and sectional area is 50 cm2.Effective stress at middle of sample of γsat= 2t/m3,is __________.
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Solution
QUESTIONS CARRY 2 MARKS EACH
The depth of flow in an alluvial channel is 1.5 m. If critical velocity ratio is 1.1 and Manning’s n is 0.018, the critical velocity of the channel as per Kennedy’s method is __________.
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Solution
Critical velocity ratio,m = 1.1
D = 1.5 m
n = 0.018
From Kennedy method
V0= 0.55 mD0.64
= 0.55 × 1.1 × (1.5)0.64
= 0.784m/sec
QUESTIONS CARRY 2 MARKS EACH
An infinite slope is to be constructed in a soil. The effective stress strength parameters of the soil are c = 0 and f= 30°.The saturated unit weight of the slope is 20 kN/m3 and the unit weight of water is 10kN/m3. Assuming that seepage is occurring parallel to the slope, the maximum slope angle fora factor of safety of 1.5 would be __________.
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Solution
QUESTIONS CARRY 2 MARKS EACH
A staff reading at a distance of 80m from a level with the bubble at its centre is 1.52m and when the bubble moved 5 divisions out of the centre, the reading is 1.6m. The angular value of 1 division of bubble is
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Solution
The length of a baseline measured on ground at on elevation of 300m a love msl is 2250m. The required correction to reduce to sea level length (radius, R= 6370 km).
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Solution
A liquid of density rand dynamic viscosity µ is flows steadily down an inclined plane in a thin sheet of constant thickness. Neglecting air friction, the shear stress on the bottom surface due to liquid flow is (θ made with horizontal)
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Solution
Self wt, w =(ρg)V
= (ρg) (At)
Resolving along inclined plane,
(ρg) (At) sinθ
Equating in inclined direction(ρg) (At) sinθ= τA
∴ Shear stress, τ = ρ gtsinθ
An air parcel having 40°C temperature moves from ground level to 500m elevation in dry air following “adiabatic lapse rate”. The resulting temperature of air parcel at 500m elevation will be
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Solution
Settling test on a sample draw from aeration tank liquor of ASP (MLSS = 2800 mg/l) was carried out with 1 litre sample.The test yielded a settled volume of 200 ml. The value of studge volume index is.
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Solution
Secondary effluent from a municipal waste plant is discharged into a stream at rate of 12000m3/ day at 20°C with BODs of 50mg/l, a dissolved oxygen concentration of 2mg/l. The streem flow is estimated to be 40,000m3/day, and water quality, parameters in the upstream of efficient outfall are:
BODs of 3mg/l, dissolved oxygen 7mg/l at 20°C.
Assume a decay constant for the mixture to be K = 0.23.
Find the ultimate BOD.
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Solution
The base width of an elementary profile of a gravity dam of height H is b. The specific gravity of material of dam is G and uplift pressure coefficient is K. The correct relationship for no tension at heel is given by