CE-2. This question consists of TWENTY FIVE sub-questions (2.1 – 2.15) of TWO marks each. For each of these sub-questions four possible answers (A, B, C and D) are given, out of which ONLY ONE is correct. Answer each sub question by darkening the appropriate bubble on the OBJECTIVE RESPONSE SHEET (ORS) using a soft HB pencil. Do not use the ORS for any rough work. You may use the Answer Book for any rough work, if needed.

2.0 An infinite slope is to be constructed in a soil. The effective stress strength parameters of the soil are c’=O and f ‘= 30°. The saturated unit weight of the slope is 20 kN/m 3 and the unit weight of water is 10 kN/m 3. Assuming that seepage is occurring parallel to the slope, the maximum slope angle for a factor of safety of 1.5 would be:

(A) 10.89°

(B) 11.30°

12.48°

14.73′°

2.1 If the effective stress strength parameters of a soil are c’=10 kPa and 0′=30°, the shear strength on a plane within the saturated soil mass at a point where the total normal stress is 300 kPa and pore water pressure is 150 kPa will be:

90.5 kPa

96.6 kPa

101.5 kPa

1O5.5.kPa

2.2 The time for a clay layer to achieve 85% consolidation is 10 years. If the layer was half as thick, 10 times more permeable and 4 times more compressible then the time that would be required to achieve the same degree of consolidation is:

1 year

5 years

12 years

16 years

2.3 In a triaxial test carried out on a cohesion less soil sample with a cell pressure of

20 kPa, the observed value of applied stress at the point of failure was 40 kPa. The angle of internal friction of the soil is:

10°

15°

25°

30°

2.4 In a falling head permeability test the initial head of 1.0 m dropped to 0.35 m in 3 hours, the diameter of the stand pipe being 5 mm. The soil specimen was 200 mm long and of 100 mm diameter. The coefficient of permeability of the soil is:

4.86 x 10 -5 cm/s

4.86 X 10 -6 cm/s

4.86 x 10 -7 cm/s

4.86 x 10 -8 cm/s

2.5 In a lined rectangular canal, the Froude number of incoming flow is 3.0. A hydraulic jump forms when it meets the pool of water. The depth of flow. after the jump formation is 1.51 m. Froude number of flow after the hydraulic jump is:

0.30

0.71

0.41

none of the above

2.6 A pump can lift water at a discharge of 0.15 m 3/s to a head of 25 m. The critical cavitation number ( s c ) for the pump is found to be 0.144. The pump is to be installed at a location where the barometric pressure is 9.8 m of water and the vapour pressure of water is 0.30 m of water. The intake pipe friction loss is 0.40 m. Using the minimum value of NPSH (Net Positive Suction Head), the maximum allowable elevation above the sump water surface at which the pump can be located is:

(A) 9.80 m

(B) 6.20 m

(C) 5.50 m

(D) none of the above

2.7 During a 6- hour storm, the rainfall intensity was 0.8 cm/hour on a catchment of area 8.6 km 2. The measured runoff volume during this period was 2,56,000 m 3. The total rainfall was lost due to infiltration, evaporation, and transpiration (in cm/hour) is

0.80

0.304

0.496.

sufficient il1fonnation not available

2.8 The rainfall on five successive days in a catchment were measured as 3, 8, 12,6, and 2 cms. If the total runoff at the outlet from the catchment was 15 cm, ,the value of the f -index (in mm/hour) is

0.0

1.04

1.53

sufficient information not available

2.9 A canal was designed to supply the irrigation needs of 1200 hectares of land growing rice of 140 days base period having a Delta of 134 cms. If this canal water is used to irrigate wheat of base period 120 days having a Delta of 52 cm, the area (in Hectares) that can be irrigated is:

(A) 2650

(B) 3608

(C) 543

(D) none of the above

2.10 For a water treatment plant having a flow rate of 432 m 3/hr, what is the required

plan area of a Type I settling tank to remove 90% of the particles having a settling velocity of 0.12 cm/sec is

(A) 120 m 2

(B) 111 m 2

(C) 90 m 2

(D) 100 m 2

2.11 The theoretical oxygen demand of a 0.001 mol/L glucose solution is

(A) 180 mg/L

(B) 192 mg/L

(C) 90 mg/L

(D) 96 mg/L

2.12 waste water sample has an initial BOD of 222 mg/L. The first order BOD decay coefficient is 0.4/day. The BOD consumed (in mg/L) in 5 ‘days is:

150

192

30

50

2.13 car is moving at a speed of 72 km/hr on a road having 2% upward gradient. The driver applies brakes when he sees an obstruction. If his reaction time is 1.5 seconds, assuming that the co-efficient of friction between the pavement and tire as 0.15, calculate the distance traversed before the car finally stops.

24 m

150 m

1056 m

324 m

2.14 The average daily traffic on a stretch of road is 300 commercial vehicles per lane per day. Design traffic repetitions for 10 years when vehicle damage factor is 2,5 and traffic growth rate is 7%, is .

3.8 msa

23.5 msa

45.4 msa

16 msa

2.15 In a concrete pavement

temperature stress is tensile at bottom during day time

load stress is compressive at bottom

(A) Both the statements (a) and (b) are correct

(B) Statement (a) is correct and (b) is wrong.

(C) Statement (b) is wrong and (a) is correct

(D) Both statements (a) and (b) are incorrect

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