Critical Hydraulic Gradient Calculator (Quicksand)
Upward gradient that floats the soil — boiling/piping check for excavations.
When upward seepage force equals buoyant weight, sand turns to liquid — workers and excavators sink. Sheet-pile penetration depth exists mostly to stretch the seepage path below this gradient.
Formula
Critical Hydraulic Gradient Calculator (Quicksand) is a free critical hydraulic gradient for geotechnical engineers and foundation designers — 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 Critical Hydraulic Gradient Calculator (Quicksand)
Upward gradient that floats the soil — boiling/piping check for excavations. The calculation implements i_cr = (G_s − 1)/(1 + e) ≈ 1.0 for most sands (Terzaghi; cofferdam design practice). When upward seepage force equals buoyant weight, sand turns to liquid — workers and excavators sink. Sheet-pile penetration depth exists mostly to stretch the seepage path below this gradient.
How to use Critical Hydraulic Gradient Calculator (Quicksand)
- 1Enter Specific gravity G_s.
- 2Enter Void ratio e.
- 3Enter Actual upward gradient at base.
- 4Read Critical gradient i_cr, FS against boiling instantly — no submit button needed.
Why use Critical Hydraulic Gradient Calculator (Quicksand)?
- ✓Implements the standard formula — i_cr = (G_s − 1)/(1 + e) ≈ 1.0 for most sands
- ✓Reference cited on-page: Terzaghi; cofferdam design practice
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Critical Hydraulic Gradient Calculator (Quicksand) use?+
It computes i_cr = (G_s − 1)/(1 + e) ≈ 1.0 for most sands, per Terzaghi; cofferdam design practice. 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?+
When upward seepage force equals buoyant weight, sand turns to liquid — workers and excavators sink. Sheet-pile penetration depth exists mostly to stretch the seepage path below this gradient.
Can this replace a soil investigation?+
No calculator replaces boreholes and lab tests — 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 Critical Hydraulic Gradient Calculator (Quicksand) free to use?+
Yes — 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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