Quiz: Civil Engineering

Exam: DFCCIL EXECUTIVE

Topic: MISCELLANEOUS

Each question carries 1 mark

Negative marking: 1/4 mark

Time: 10 Minutes

Q1. In surveyor’s compass, the graduated ring is attached to the:

(a) Box

(b) Needle

(c) Sigh vane

(d) Jewel bearing

Q2. The imaginary line passing through the intersection of cross hairs and the optical center of the objective is known as ……….

(a) Line of sight

(b) Line of collimation geoid

(c) Axis of the telescope

(d) None of these

Q3. The ‘fix’ of a plane table with three known points is good if the instrument station lies: –

(a) in the great triangle

(b) outside the greater triangle

(c) outside the great triangle but within the great circle

(d) on the circumference of the circumscribing circle

Q4. If a transition curve is introduced between a straight and a curve such that a super elevation of 15 cm is introduced over a curve and if the rate of super elevation is 1 IN 500, then the length (m) of the transition curve will be

(a) 50.00

(b) 75.00

(c) 100.00

(d) 150.00

Q5. The length of long chord and tangent of a circular curve if radius R will be equal, if the angle of deflection is

(a) 30°

(b) 90°

(c) 60°

(d) 120°

Q6. A soil engineer collects a sample of soil which having moist unit weight of a soil is 25 kN/m³, water content available is 50% and the specific gravity of the solid of the soil is 2.55. then, what is the value of porosity of soil mass? (Assume unit weight of water = 9.81 kN/m³)

(a) 66 %

(b) 33 %

(c) 30 %

(d) 40 %

Q8. If pressure due to submerged weight of the soil is equal to the seepage pressure, the effective pressure:

(a) Remains the same

(b) Becomes zero

(c) Becomes unity

(d) Becomes maximum

SOLUTION

S1. Ans.(a)

Sol. In surveyor compass the graduated ring fixed at the box & moves with the box while the magnetic needle remain’s stationary along the north south line.

S2. Ans.(b)

Sol. line of sight. The line passes through optical centre of objective & intersection of cross hair is called as line of sight.

Line of collimation – When line of sight become horizontal. It will be known as line of collimation

Axis of telescope – This is an imagionary line joining point’s of optical centre of eyepiece to the optical centre of objective glass.

Axis of bubble tube – This is an imagionary line which is tangential on longitudenal curve of bubble tube.

S3. Ans.(a)

Sol. According to lehmans rule, the ‘fix’ of a plane table with three known points is good if the instrument station lies in the great triangle & is bad if the plane table station lies on the circumference of the circumscribing circle.

S4. Ans.(b)

Sol. super elevation (e) = 15 cm.

Rate of super elevation = 1 in 500

Length of transition curve = 500 ×0.15

= 75 metre.

S5. Ans.(d)

Sol. length of long chord = tangent length

2R sin ∆/2=R tan ∆/2

cos ∆/2 =1/2

▭(∆/2=60) ▭(∆ =120°)

S6. Ans.(b)

Sol. unit weight of soil (r_b ) = 25 kN/m³

Water content (w) = 50%

Specific gravity (G) = 2.55

Porosity (n) = ?

r_d= r_b/(1+w)=Grw/(1+e)

=25/(1+0.5 )=(2.55×9.81 )/(1+e)

▭(e=0.50)

n=e/(1+e)=0.5/1.5

▭(n=0.33)

S7. Ans.(a)

Sol. for laminar flow condition in saturated soil, the rate of percolation is directly proportional to hydraulic gradient.

▭(V α i)

S8. Ans.(b)

Sol. if pressure due to submerged weight of the soil is equal to the seepage pressure, the effective pressure becomes zero.

S9. Ans.(b)

Sol.

Coefficient Unit

Coefficient of compressibility

Coefficient of consolidation

Coefficient of volume compressibility m^2/kN

m^2/sec

m^2/kN

S10. Ans.(b)

Sol. degree of consolidation

(a) when settlement at any stage is known.

▭(%U=∆h/∆H×100 )

∆h → settlement after time ‘t’

∆H → ultimate consolidation settlement

(b) when pore pressure is known

▭(%U=(ui-u)/(ui-0)×100)

u → pore water pressure after time ‘t’

ui → pore water pressure at the beginning of consolidation

(c) when void ratio is known –

▭(% U=(e_0-e)/(e_0-e_100 )×100)

e_o→ void ratio at the beginning

e → void ratio after time ‘t’

e_100 → final void ratio at the end.