Question

The working chamber of pneumatic caissons are kept airtight because ________

(a) To avoid tilting

(b) To remove the soil

(c) To prevent water from entering the chamber

(d) None of the mentioned

I got this question in an internship interview.

My question is taken from Well Foundations in portion Well Foundations of Geotechnical Engineering II

Answer 1

Correct choice is (c) To prevent water from entering the chamber

For explanation: In order that sub-soil water may not enter the working chamber, the pressure of air in the shaft is kept airtight.