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GATE 2016 CE (CE1) – Question 22

Geotechnical Engineering · Three-phase system, phase relationships, index properties and soil classification · 1 mark · Multiple choice

A fine-grained soil is plastic at water contents between 26% and 48%. Under the Indian Standard classification system, it is ______.

  1. CL
  2. CH
  3. CL-ML
  4. CI

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Correct answer: (D) CI

Explanation

The lower and upper plastic-state limits are PL=26% and LL=48%, so PI=22%. The A-line ordinate at LL48 is0.73(48−20)=20.44%, and the point lies above it, indicating clay. LL lies in the intermediate-compressibility band35–50%, giving **CI, D**.