# Environmental Engineering Questions and Answers – Forces and Loads on Sewer

This set of Environmental Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Forces and Loads on Sewer”.

1. The magnitude of hoop stress on sewer is given __________
a) PD/2t
b) PD/t
c) 2PD/t
d) PD/2

Explanation: The magnitude of hoop stress on sewer is given by PD/2t where, P is the internal pressure, D is the diameter of sewer and t is the thickness of the shell.

2. In order to reduce temperature stress ______________ joints are provided.
a) Contraction
b) Expansion
c) Bell and spigot
d) Collar

Explanation: In order to reduce temperature stress, expansion joints are provided at intervals of 20m to 30m.

3. The expression for the temperature stress is given by __________
a) EPαt
b) EPαt/2
c) 2EPαt
d) EP/αt

Explanation: The expression for the temperature stress is given by EPαt where, EP is the modulus of elasticity of pipe, α is the coefficient of thermal expansion and ‘t’ is the change in temperature.

4. The type of backfill is saturated clay. What is its unit weight?
a) 1040kg/m3
b) 2080kg/m3
c) 2000kg/m3
d) 1500kg/m3

Explanation: When the type of backfill is saturated clay, then its unit weight is 2080kg/m3.

5. Which of the following has the minimum unit weight?
a) Dry sand
b) Wet sand
c) Damp clay
d) Ordinary sand

Explanation: The unit weight of wet sand, damp clay, ordinary sand and dry sand are 1920kg/m3, 1920kg/m3, 1840kg/m3 and 1600kg/m3 respectively.

6. The type of soil is loose dry sand. What is the coefficient of cohesion of the soil?
a) 100
b) 200
c) 500
d) 0

Explanation: Loose dry sand is a cohesionless soil. So, the value of the coefficient of cohesion is 0.

7. Which of the following order is correct regarding coefficient of cohesion?
a) Hard clay < Dense sand > Medium clay > Soft clay
b) Hard clay > Dense sand > Medium clay > Soft clay
c) Medium clay > Dense sand > Hard clay > Soft clay
d) Dense sand > Medium clay > Hard clay > Soft clay

Explanation: The coefficient of cohesion of Hard clay, Dense sand, Medium clay and Soft clay are 4700kg/m2, 1400kg/m2, 1200kg/m2 and 200kg/m2 respectively.

8. How many types of underground sewer are there on the basis of construction conditions?
a) 2
b) 3
c) 4
d) 5

Explanation: Depending upon the type of the construction conditions, underground sewers are of 3 types, namely Trench ditch condition, Embankment condition and Tunnel condition.

9. _______ condition exists when the sewer is laid at a depth between 9m to 12m.
a) Trench ditch
b) Trench
c) Tunnel
d) Embankment

Explanation: Tunnel condition exists when the sewer is laid at a depth between 9m to 12m. This process is done by jacking or by tunneling.

10. Negative projecting condition is a type of ______ condition.
a) Trench ditch
b) Trench
c) Tunnel
d) Embankment

Explanation: Negative projecting condition exists when the trench is narrower with respect to the size of the pipe and shallow with respect to the depth of cover.

Sanfoundry Global Education & Learning Series – Environmental Engineering.

To practice all areas of Environmental Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

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