Geotechnical Engineering

Well Foundations

Question 1
Marks : +2 | -2
Pass Ratio : 100%
The method of construction of pneumatic caisson is similar to ________
Box caissons
Open caissons
Rectangular caissons
All of the mentioned
Explanation:
The method of construction of pneumatic caisson is similar to that for open caissons (well) except that the working chamber is kept air tight.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
In order to prevent leakage of air in the working chamber ________ is provided.
Arrangement of double gates
Air compressor
Air lock
All of the mentioned
Explanation:
In order to prevent leakage of air, the arrangement of double gates is provided. The person enters the first gate, where pressure is atmospheric.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
The allowable pressure that is allowed inside the working chamber of pneumatic caissons is _______
2 kg/cm2
4 kg/cm2
3.5 kg/cm2
7 kg/cm2
Explanation:
Normally the tolerable air pressure under which a man can work is limited to 3.5 kg/cm2 in pneumatic caissons.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
The limiting head of water value in pneumatic caisson is ________
40 m
25 m
35 m
50 m
Explanation:
As the maximum air pressure is limited to 3.5 kg /cm2. the limiting head of water is given by:
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Disadvantage of using pneumatic caissons are ________
Process cannot be done under control conditions
Sinking process is tedious
Inspection process is time consuming
All of the mentioned
Explanation:
In pneumatic caissons, the sinking of pneumatic caissons are tedious, time consuming and expensive.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Pneumatic caissons are closed at _________ during construction.
Bottom
Top
Top and bottom
None of the mentioned
Explanation:
Pneumatic caissons are closed at the top and open at the bottom during construction.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
The essential feature of a pneumatic caissons are __________
Tilting can be avoided and Removing water by Compressed air
Skin fraction is zero
None of the mentioned
All of the mentioned
Explanation:
The essential feature of a pneumatic caisson is that compressed air is used to exclude or remove water from the working chamber at the bottom.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Advantage of using pneumatic caissons are _________
Affords easy inspection and Process is done under control conditions
Sinking process is easy
None of the mentioned
All of the mentioned
Explanation:
An advantage of pneumatic caisson is that the entire process of sinking well is carried out under controlled conditions and it affords easy inspection work.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
The working chamber of pneumatic caissons are kept airtight because ________
To avoid tilting
To remove the soil
To prevent water from entering the chamber
None of the mentioned
Explanation:
In order that sub-soil water may not enter the working chamber, the pressure of air in the shaft is kept airtight.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
In order to assist sinking of well __________ method is used in pneumatic caissons.
Air pressure is reduced and Using explosive
Using airlocks
None of the mentioned
All of the mentioned
Explanation:
In order to assist sinking process, air pressure may be reduced for a short while. Sometimes explosive may be employed in this case, it is essential to make arrangements for the immediate removal of fall fumes.