Field entry of permeability tests, automated calculation of the K coefficient (hemispherical formula) and direct comparison with the theoretical K adopted by the GEP Modelling module. PDF report sheets ready to attach to a Water Act file.
Landmark, date, hole diameter and depth (cm), geological facies, volume poured (L), drainage time (s) and safety coefficient Cs. Unlimited test entry, organised by project.
Hemispherical formula (t1=0, h2=0): K = R ÷ (2×t) × ln(1 + 2×H1 ÷ R), with H1 = volume poured ÷ (π×R²). All lengths are entered in centimetres; the calculation automatically converts to the standard hydrogeological unit (m/s).
Kdim = K ÷ Cs (safety coefficient, 1.5 by default). Value directly usable for sizing an infiltration structure.
Deviation = log10(field Kdim ÷ GEP Kdim). Agreement validated if |deviation| ≤ 0.5 (factor ~3.16), consistent with the geological accuracy of the BRGM module. Measured K then takes precedence over the literature estimate.
Visualisation of the infiltration curve per test and a multi-test summary for a given project (summary table, agreement badges).
Generation of a PDF report sheet per test. JSON export/import (all tests or a single test) for archiving or direct transfer to GEP Modelling.
The Porchet test consists of drilling a vertical hole with an auger, saturating the soil, then pouring a known volume of water (V) and measuring the time (t) needed for the hole to fully drain.
K = R ÷ (2×t) × ln(1 + 2×H1 ÷ R), where R = hole radius, H1 = initial water height = volume poured ÷ (π×R²).
All lengths (diameter, depth, calculated radius, water height H1) are entered and displayed in centimetres (cm) to avoid any mixing of units. Only permeability (K, Kdim) remains in m/s, the standard hydrogeological unit used by the GEP Modelling software — the internal calculation automatically converts cm to metres for this step.
Kdim = K ÷ Cs (safety coefficient, 1.5 by default).
Order-of-magnitude reasoning — deviation = log10(field Kdim ÷ GEP Kdim), considered in agreement if |deviation| ≤ 0.5 (factor ~3.16, consistent with the geological accuracy stated by the BRGM module).
The software does not replace the engineer's expertise, nor any requirements from the DDT(M), the DREAL, the project owner or the inspection body.
One sheet per test: location, facies, raw data, K / Kdim result, GEP comparison, agreement badge.
All tests from a project, or a single test — for archiving, sharing between workstations or transfer to the GEP module.
Summary table of all tests performed on a site, with agreement badges per test.
Annual subscription — 1 seat
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Used together with GEP Modelling (€5,500 excl. tax/year) to support a Water Act file with field measurements. Training or tailored regulatory support: on request — contact GMEP.