Unconfined Compressive Strength (UCS) Calculator
qu and undrained shear strength from an unconfined compression test, with the area correction and consistency verdict.
The area correction matters โ a specimen bulges as it strains, so skipping it overstates strength ~8% at 8% strain. UCS assumes ฯ=0 saturated clay; it's meaningless on sands, which can't stand unconfined.
Formula
Note: Educational aid โ foundation design needs lab-certified strengths.
Unconfined Compressive Strength (UCS) Calculator is a free unconfined compressive strength for geotechnical engineers and foundation designers โ instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Unconfined Compressive Strength (UCS) Calculator
qu and undrained shear strength from an unconfined compression test, with the area correction and consistency verdict. The calculation implements A_c = Aโ รท (1 โ ฮต); qu = P รท A_c; su = qu รท 2 (IS 2720 Part 10; ASTM D2166; Terzaghi consistency scale). The area correction matters โ a specimen bulges as it strains, so skipping it overstates strength ~8% at 8% strain. UCS assumes ฯ=0 saturated clay; it's meaningless on sands, which can't stand unconfined.
How to use Unconfined Compressive Strength (UCS) Calculator
- 1Enter Failure load in N.
- 2Enter Specimen diameter in mm.
- 3Enter Axial strain at failure in %.
- 4Read UCS qu, Undrained strength su = qu/2 instantly โ no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Unconfined Compressive Strength (UCS) Calculator?
- โImplements the standard formula โ A_c = Aโ รท (1 โ ฮต); qu = P รท A_c; su = qu รท 2
- โReference cited on-page: IS 2720 Part 10; ASTM D2166; Terzaghi consistency scale
- โOne-click SI โ Imperial toggle โ values convert in place, physics stays in SI
- โLive worked example: the substitution recomputes from your numbers
- โBuilt-in engineering verdict flags out-of-range results instantly
- โRuns entirely in your browser โ nothing uploaded, free forever
Frequently asked questions
What formula does the Unconfined Compressive Strength (UCS) Calculator use?+
It computes A_c = Aโ รท (1 โ ฮต); qu = P รท A_c; su = qu รท 2, per IS 2720 Part 10; ASTM D2166; Terzaghi consistency scale. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
The area correction matters โ a specimen bulges as it strains, so skipping it overstates strength ~8% at 8% strain. UCS assumes ฯ=0 saturated clay; it's meaningless on sands, which can't stand unconfined. Note: Educational aid โ foundation design needs lab-certified strengths.
Can this replace a soil investigation?+
No calculator replaces boreholes and lab tests โ but with investigated parameters in hand, this gives you the standard-method result instantly, with the formula shown so reviewers can check it.
Is the Unconfined Compressive Strength (UCS) Calculator free to use?+
Yes โ completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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