Soil Exploration MCQs – Part 1

Practice SSC JE and other civil engineering exam questions on soil exploration: planning boreholes, the standard penetration test (SPT), N-value corrections, SPT values for clays, and disturbed and undisturbed sampling. Tap an option to check it, then open the full explanation for each question.

Question 1Easy

In soil mechanics, the number and disposition of bore holes are varied depending upon the ______.

Full explanation

Answer: C. subsoil condition

More boreholes, more closely spaced, are needed where the subsoil is variable or erratic.

Question 2Easy

In a standard penetration test, what are the weight of the hammer and the dropping height as per IS 2131-1981?

Full explanation

Answer: D. 63.5 kg, 750 mm

SPT hammer: 63.5 kg falling freely through 750 mm.

Question 3Medium

The observed N-value of an SPT test is 21. The N-value after correcting for dilatancy is:

Full explanation

Answer: B. 18

N = 15 + ½(21 − 15) = 18.

Question 4Easy

Standard penetration resistance in very stiff clays lies between:

Full explanation

Answer: D. 15 and 30

Very stiff clay: N between 15 and 30.

Question 5Easy

Undisturbed samples are obtained by:

Full explanation

Answer: B. Thin walled samplers

Thin-walled tube samplers (e.g. Shelby tubes) displace little soil, so they recover undisturbed samples.