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GATE 2024 CE (CE1) – Question 46

Geotechnical Engineering · Shear strength, Mohr circle, stress-strain characteristics, stress paths · 2 marks · Multiple select

Which of the following statement(s) is/are CORRECT?

  1. Swell potential of soil decreases with an increase in the shrinkage limit.
  2. Both loose and dense sands with different initial void ratios can attain similar void ratio at large strain during shearing.
  3. Among the several corrections to be applied to the SPT-N value, the dilatancy correction is applied before all other corrections.
  4. In electrical resistivity tomography, the depth of current penetration is half of the spacing between the electrodes.

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Show answer and explanation

Correct answer: (A) Swell potential of soil decreases with an increase in the shrinkage limit.; (B) Both loose and dense sands with different initial void ratios can attain similar void ratio at large strain during shearing.; (C) Among the several corrections to be applied to the SPT-N value, the dilatancy correction is applied before all other corrections.; (D) In electrical resistivity tomography, the depth of current penetration is half of the spacing between the electrodes.

Explanation

A: a higher shrinkage limit means that the soil starts to shrink at a higher water content and has a lower volume change potential, so the swell potential is lower. B: during shearing, loose sand contracts and dense sand dilates, and both approach the critical void ratio at large strains. C: in IS 2131 the observed N is first corrected for dilatancy (for fine or silty sand below the water table) and then for overburden. D: for the common arrays, the depth of investigation is about half the electrode spacing.