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Sampler disturbed or undisturbed check

Short answer

Area ratio Ar=(42²−40²)/40²×100 = 10.25%. Since Ar slightly exceeds the 10% limit for undisturbed samples, the sample is disturbed.

The internal diameter of a sampler is 40 mm and the external diameter is 42 mm. Will you consider the sample obtained from the sampler as disturbed or undisturbed?

Take the 40 mm as the inside diameter D1D_1 and the 42 mm as the outside diameter D3D_3 of the cutting edge (wall 1 mm thick).

Ar=D32−D12D12×100=422−402402×100=1641600×100=10.25%A_r = \frac{D_3^2-D_1^2}{D_1^2}\times100 = \frac{42^2-40^2}{40^2}\times100 = \frac{164}{1600}\times100 = 10.25\%

The limit for an undisturbed sample is Ar≤10%A_r \le 10\%. Since Ar=10.25%A_r = 10.25\% is slightly greater than 10%, the sample is classed as disturbed (marginal; it may be accepted as nearly undisturbed in soft or stiff clay if the clearances are right, but by the criterion it is not).

✓ Answer checked by Claude Sonnet 5.5

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