Question

The significant depth is assumed up to a level at which the net increase in vertical pressure becomes _______ of initial overburden pressure.

(a) 10% to 20%

(b) less than 10%

(c) 20% to 30%

(d) 50% to 70%

This question was posed to me in exam.

My doubt stems from Soil Samples and Samplers in division Stabilisation of Soils, Site Investigation and Sub – Soil Exploration of Geotechnical Engineering II

Answer 1

Correct choice is (b) less than 10%

Best explanation: The significant depth is assumed up to a level at which the net increase in vertical pressure becomes less than 10% of initial overburden pressure. Also a pressure bulb bounded by an isobar of 1/5 or 1/10 of the surface loading intensity is assumed as minimum depth of exploration.