Direct shear test calculator

Inputs in the worked example

The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.

Worked example — results

• ✓ Fit R² ≥ 0.95
• ✓ Cohesion intercept small (≤ 15 kPa)

Method, formulas and assumptions

• Least-squares line τ = c′ + σn·tan φ′ through peak points
• Residual line from post-peak values
• Consider forcing c′ = 0 for uncemented sands

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