Stress Increase at Depth (2:1 Method)
Pressure felt at depth under a footing by the 2:1 spread approximation.
At z = B the stress has already halved; at 2B it's ~25%. This dying-with-depth is why settlement analyses stop at ~2B โ and why neighbouring footings overlap stresses when closer than that.
Formula
Stress Increase at Depth (2:1 Method) is a free 2:1 method 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 Stress Increase at Depth (2:1 Method)
Pressure felt at depth under a footing by the 2:1 spread approximation. The calculation implements ฮฯ = qยทBยทL/((B+z)(L+z)) (2:1 approximation; Boussinesq comparison). At z = B the stress has already halved; at 2B it's ~25%. This dying-with-depth is why settlement analyses stop at ~2B โ and why neighbouring footings overlap stresses when closer than that.
How to use Stress Increase at Depth (2:1 Method)
- 1Enter Footing contact pressure in kPa.
- 2Enter Footing width in m.
- 3Enter Footing length in m.
- 4Enter Depth below footing in m.
- 5Read Stress increase ฮฯ at z instantly โ no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Stress Increase at Depth (2:1 Method)?
- โImplements the standard formula โ ฮฯ = qยทBยทL/((B+z)(L+z))
- โReference cited on-page: 2:1 approximation; Boussinesq comparison
- 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 Stress Increase at Depth (2:1 Method) use?+
It computes ฮฯ = qยทBยทL/((B+z)(L+z)), per 2:1 approximation; Boussinesq comparison. 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?+
At z = B the stress has already halved; at 2B it's ~25%. This dying-with-depth is why settlement analyses stop at ~2B โ and why neighbouring footings overlap stresses when closer than that.
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 Stress Increase at Depth (2:1 Method) 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.
Related Engineering tools
Reynolds Number Calculator
Compute Re from density, velocity, pipe diameter and viscosity โ with instant laminar/turbulent classification.
โ LiveLaminar vs Turbulent Flow Classifier
Classify hydraulic-oil or process-fluid flow regime from kinematic viscosity, line velocity and tube bore.
โ LiveBernoulli Equation Solver
Solve downstream pressure between two points from velocities, elevations and fluid density (ideal, lossless).
โ Live