Effective Stress Calculator
Total, pore and effective stress at depth with a water table.
Soil strength and stiffness obey ฯโฒ, never ฯ. A rising water table weakens the ground without adding a single newton of load โ the mechanism behind most rain-triggered failures.
Formula
Effective Stress Calculator is a free effective stress 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 Effective Stress Calculator
Total, pore and effective stress at depth with a water table. The calculation implements ฯโฒ = ฯ โ u (Terzaghi, 1925 โ THE equation of soil mechanics) (Terzaghi's principle; any geotechnical text). Soil strength and stiffness obey ฯโฒ, never ฯ. A rising water table weakens the ground without adding a single newton of load โ the mechanism behind most rain-triggered failures.
How to use Effective Stress Calculator
- 1Enter Depth of interest in m.
- 2Enter Water table depth in m.
- 3Enter Unit weight above WT in kN/mยณ.
- 4Enter Saturated unit weight below in kN/mยณ.
- 5Read Total stress ฯ, Pore pressure u, Effective stress ฯโฒ instantly โ no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Effective Stress Calculator?
- โImplements the standard formula โ ฯโฒ = ฯ โ u (Terzaghi, 1925 โ THE equation of soil mechanics)
- โReference cited on-page: Terzaghi's principle; any geotechnical text
- โOne-click SI โ Imperial toggle โ values convert in place, physics stays in SI
- โLive worked example: the substitution recomputes from your numbers
- โRuns entirely in your browser โ nothing uploaded, free forever
Frequently asked questions
What formula does the Effective Stress Calculator use?+
It computes ฯโฒ = ฯ โ u (Terzaghi, 1925 โ THE equation of soil mechanics), per Terzaghi's principle; any geotechnical text. 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?+
Soil strength and stiffness obey ฯโฒ, never ฯ. A rising water table weakens the ground without adding a single newton of load โ the mechanism behind most rain-triggered failures.
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 Effective Stress 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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