80.

81.

82.

83.

84.

85.

86.

87.

102/21

In an upflow anaerobic sludge blanket reactor, the ratio of reactor volume (V) to flow
rate (Q) is called

A) Hydraulic Retention Time B) Solid Retention Time

C) Sludge Retention Time D) Blanket Retention Time

Determine the coefficient of permeability of soil (mm/s) in a constant head permeability
test, in which the distance between piezometer tappings is 120 mm, area of the test
sample is 100 mm? and the difference of water levels in the piezometers is 60 mm.
600 ml of water is collected in 300 seconds during the test.

A) 0.01 B) 0.04 C) 0.06 D) 0.09

Find the effective stress at the bottom of a sand deposit of thickness 8 m. Water
table is at the middle of the sand deposit. Take y = 18 (1/73, Yeat = 20 ۴۲۷/۳,
% = 10 kN/m8,

A) 152 B) 132 C) 112 D) 102

Aclay layer 6 m thick is subjected to a pressure of 60 KN/m2. If the layer has a double
drainage and undergoes 50% consolidation in one year, determine the coefficient of
consolidation in m?/year. Take T, = 0.196.

A) 1.764 B) 1.250 C) 0.112 D) 0.156

Taylor's stability charts are based on the total stresses using
A) Bishop’s method B) Friction circle method
C) 0-0 analysis D) None of the above

Curve joining points of equal stress intensity
A) 15010165 ©) Isochrones
C) Isohyets D) 1500815

What is the intensity of vertical stress in kN/m? below a point load of 500 kN at a
depth of 5m?
A) 8.54 B) 10.43 C) 9.55 D) 6.22

Determine the total lateral earth pressure at rest in kN on a retaining wall of height
ടന. Take ‏رزوي‎ = 17 ۴۷۸۵۶ and ‏وكا‎ = 0.5. Assume water table is below 5 ന.

A) 106.25 B) 110.54

C) 102.32 D) 115.12

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