GATE 2022 CE (CE2) – Question 31

Geotechnical Engineering · Sub-surface investigations: boring, SPT, CPT, plate load test · 1 mark · Numerical answer

The inside diameter of a sampler tube is 50 mm. The inside diameter of the cutting edge is kept such that the Inside Clearance Ratio (ICR) is 1.0 % to minimize the friction on the sample as the sampler tube enters into the soil. The inside diameter (in mm) of the cutting edge is _________________. (round off to two decimal places)

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Correct answer: 49.25 to 49.75

Explanation

Inside clearance ratio is $100(D_t-D_c)/D_c$, where Dₜ is tube inside diameter and D꜀ is cutting-edge inside diameter.

Thus $0.01=(50-D_c)/D_c$, giving $D_c=50/1.01=49.50495$ mm. **Answer: 49.50 mm**.