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This set of Irrigation Engineering Multiple Choice Questions & Answers (MCQs) focuses on Irrigation Engineering Set 3
Q1 | When the upstream face of a gravity dam is vertical, then the intensity of water pressure atthe water surface and at the base respectively will be (where w is unit weight of water and H is the depth of water.)
- 0 and wH212
- wH2/2and wH2/3
- wH and 0
- OandwII
Q2 | The uplift pressure on a dam can be controlled byi) constructing cutoff under upstream faceii) constructing drainage channels bet-ween the dam and its foundationiii) by pressure grouting in foundationThe corret answer is
- only (i)
- both (i) and (ii)
- both (i) and (iii)
- (i), (ii) and (iii)
Q3 | The uplift pressure on the face of a drainage gallery in a dam is taken as
- hydrostatic pressure at toe
- average of hydrostatic pressure at toe and heel
- two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel
- none of the above
Q4 | Horizontal acceleration due to earthquake results in
- hydrodynamic pressure
- inertia force into the body of the dam
- both (a) and (b)
- none of the above
Q5 | Hydrodynamic pressure due to earthquake acts at a height of
- 3H/47I above the base
- 3H747t below the water surface
- 4H/371 above the base
- 4H737t below the water surface where H is the depth of water.
Q6 | The major resisting force in a gravity dam is
- water pressure
- wave pressure
- self-weight of dam
- uplift pressure
Q7 | When the reservoir is full, the maximum compressive force in a gravity dam is produced
- at the toe
- at the heel
- within the middle third of base
- at centre of base
Q8 | The maximum permissible eccentricity for no tension at the base of a gravity dam is
- B/2
- B/3
- B/4
- B/6
Q9 | Presence of tail water in a gravity dami) increases the principal stressii) decreases the principal stressiii) increases the shear stressiv) decreases the shear stressThe correct answer is
- (i) and (iii)
- (i)and(iv)
- (ii) and (iii)
- (ii) and (iv)
Q10 | For wave action in dams, the maximum height of freeboard is generally taken to be equal to (where hw is height of wave.)
- 0.5 hw
- 0.75 hw
- 1.25 hw
- 1.50 hw
Q11 | As compared to gravity dams, earthen dams
- are costlier
- are less susceptible to failure
- require sound rock foundations
- require less skilled labour
Q12 | The most suitable material for the central impervious core of a zoned embankment typedam is
- clay
- coarse sand
- silty clay
- clay mixed with fine sand
Q13 | Seepage through embankments in an earthen dam is controlled by
- drainage filters
- relief wells
- drain trenches
- provision of downstream berms
Q14 | Seepage through foundation in an earthen dam is controlled by providing
- rock toe
- horizontal blanket
- impervious cut off
- chimney drain
Q15 | The flow of water after spilling over the weir crest in chute spillway and side channelspillway respectively are
- at right angle and parallel to weir crest
- parallel and at right angle to weir crest
- parallel to weir crest in both
- at right angle to weir crest in both
Q16 | The discharge passing over an ogee spillway is given by (where, L is effective length of spillway crest and H is the total head over the spillway crest including velocity head.)
- CLH3/2
- CHL3/2
- CLH5/2
- CLH1/2
Q17 | Coefficient of discharge of an ogee spillway
- depends on depth of approach and upstream slope
- depends on downstream apron interference and downstream submergence
- remains constant
- both (a) and (b)
Q18 | Which of the following spillways is least suitable for an earthen dam ?
- ogee spillway
- chute spillway
- side channel spillway
- shaft spillway
Q19 | In case of non-availability of space due to topography, the most suitable spillway is
- straight drop spillway
- shaft spillway
- chute spillway
- ogee spillway
Q20 | In a chute spillway, the flow is usually
- uniform
- subcritical
- critical
- super critical
Q21 | For the upstream face of an earthen dam, the most adverse condition for stability of slope is
- sudden drawdown
- steady seepage
- during construction
- sloughing of slope
Q22 | If there are two canals taking off from each flank of a river, then there will be
- one divide wall and one undersluice
- one divide wall and two undersluices
- two divide walls and one undersluice
- two divide walls and two undersluices
Q23 | Generally the weir is aligned at right angles to the direction of the main river currentbecause
- it ensures less length of the weir
- it gives better discharging capacity
- it is economical
- all of the above
Q24 | The main function of a divide wall is to
- control the silt entry in the canal
- prevent river floods from entering the canal
- separate the undersluices from weir proper
- provide smooth flow at sufficiently low velocity
Q25 | A divide wall is provided
- at right angle to the axis of weir
- parallel to the axis of weir and up-stream of it
- parallel to the axis of weir and down-stream of it
- at an inclination to the axis of weir