How we know the numbers are right.
Lives ride on these numbers. Every engine starts from a cited source and is protected by golden, regression and boundary-condition tests. Of 232 methods with a tracked validation state, 74 are released for their documented scope and 158 are regression-protected while their independent coverage grows. Every analysis page shows its own state and the evidence behind it — not one blanket badge. Not “trust us.”
Evidence is visible: source, test, benchmark or limiting solution.
Built from the source, not from memory
Every engine is coded from the governing standard, textbook or software theory manual — cited by clause. Chart-lookup factors that have no closed form are explicit inputs with documented defaults, never a guessed curve-fit. We build the method the way its author defined it.
Golden-tested against a hand-verified case
Each engine ships with a golden test: at least one hand-checked case plus the edge cases (near-zero, huge, water at surface, FoS ≈ 1) that expose the failure modes. It has to hold at the criterion boundary, not just the happy path.
Benchmark coverage is visible and growing
Where a published worked example is available, we reproduce its inputs and record the expected value. Other cited checks establish formula fidelity from the governing equation or limiting solution. A failed benchmark is a bug to investigate, not a tolerance to widen; the detailed coverage status remains explicit rather than implied.
Published benchmark cases and formula checks — documented.
A representative slice of published-value benchmarks. Each row is backed by an automated test that asserts the stated engine result against the cited source.
| Method | Validated against | We reproduce |
|---|---|---|
| FE bearing capacity (φ=0) | Prandtl (1921) | q_ult = (2+π)·cᵤ = 5.14·cᵤ |
| 2-D elasto-plastic footing FE (HS/MC BVP) | Prandtl 1921 · Vesić 1973 | q_ult → 5.14·sᵤ (φ=0) + Vesić N_c/N_q; mesh-converges to the limit |
| 3-D elasto-plastic continuum footing FE (square) | Skempton 1951 · Vesić 1973 | φ=0 square q_ult → N_c·s_c ≈ 6·sᵤ (Skempton shape factor s_c≈1.2), within the coarse-mesh band |
| FE limit analysis (bounds) | Sloan LP · Prandtl | Lower & upper bound straddle 5.14·cᵤ |
| Transient unsaturated seepage (Richards) | Celia-Bouloutas-Zarba 1990 · van Genuchten | Haverkamp-sand SWCC θ(ψ) benchmark, exact |
| Wall Boussinesq surcharge (line/point/strip) | NAVFAC DM-7.2 Fig 11 | Published σ_h·H/Q influence values across (m,n) |
| Hardening-Soil (triaxial + oedometer) | Schanz-Vermeer-Bonnier 1999 | Berlin Sand III + Hostun sand; E_oed law to <2.5% |
| HS confined & layered settlement | Hardening-Soil oedometer (closed form) | Closed-form HS oedometer integral to <2.5% |
| 1-D consolidation (time-rate) | Terzaghi | t₉₀ = 0.848·H²/cᵥ (small-strain limit) |
| Finite-strain consolidation | Gibson (nonlinear PDE) · CONDES | Power-law e–σ′–k benchmark case |
| 1-D site response (site period) | Kramer · SHAKE | T₀ = 4H/Vₛ; transfer-function peaks at f₀/3f₀/5f₀ |
| Lateral pile p-y | Reese & Van Impe · Matlock | Published p-y deflection / moment cases |
| Vertical stress increase | Boussinesq | Closed-form influence factors |
| Liquefaction triggering | Youd et al. (NCEER) · Idriss-Boulanger | Published CRR / FoS worked cases |
| Flexible pavement | IRC 37 · layered-elastic | IRC-37 worked example strains |
| Rock strength | Hoek-Brown | Published GSI / σ₁ envelope cases |
Where we draw the line
- We never invent a benchmark number. Every value in a validation test carries its source — title, author/organisation, year. If we can’t cite it, it isn’t in the suite.
- A failing benchmark is a bug, not a tolerance to widen. When a published case doesn’t match, we fix the engine and re-run — or, if the source itself is wrong, we document why with evidence.
- For frontier methods with sparse public numbers (some nonlinear FE), we gather every case we can rigorously cite and make up the balance with exact analytical / limiting solutions — and we say so, out loud, rather than pad with invented figures.
- Standards are acquired legally. We implement methods and cite clauses; we don’t redistribute copyrighted code text, tables or figures.
Run your own worked example.
Pick any analysis, drop in the inputs from a case you already trust, and check the number. That’s the whole pitch — the software should agree with the textbook.