We conduct field permeability tests (Lefranc and Lugeon) following ASTM D5092 and USBR 7300 standards. In Birmingham Alabama, the Piedmont geology — dominated by weathered phyllite, schist, and saprolite — creates highly variable hydraulic conductivity, often ranging from 10⁻⁵ to 10⁻³ cm/s within a single borehole. That variability demands in-situ measurement, not lab extrapolation. Our team deploys double-packer systems in NQ and HQ boreholes to isolate discrete zones, then runs constant-head or falling-head sequences depending on the formation response. Before mobilizing, we often cross-check with a CBR test for pavement subgrades when the project involves roadway drainage, but the core deliverable remains the hydraulic conductivity profile along the borehole axis.
Birmingham Alabama's Piedmont saprolite can yield k values spanning three orders of magnitude within 5 meters of borehole — in-situ testing is non-negotiable.
Methodology and scope
We distinguish two main approaches: the Lefranc test (constant-head in permeable soils and weathered rock) and the Lugeon test (multi-stage pressure injection in rock masses). In Birmingham Alabama, the contrast between the Valley and Ridge limestone aquifers and the Piedmont saprolite means we switch protocols mid-project. For a recent dam rehabilitation in Shades Valley, we ran Lugeon stages at 3, 6, and 10 bars, recording permeability values from 0.2 to 8 Lugeon units. The saprolite zones required constant-head Lefranc instead, with stabilization times around 45 minutes per stage. We supplement these results with discrete fracture mapping and the infiltration test for surface permeability when evaluating seepage through embankments. All data is reduced to k (m/s) or Lugeon values and reported with raw pressure-flow logs.
Technical reference image — Birmingham Alabama
Local considerations
Birmingham Alabama expanded rapidly during the post-war industrial boom, often building on steep hillsides and filled valleys without characterizing the subsurface flow regime. The result: many existing embankments, retaining walls, and buried utilities now sit in zones where perched water tables fluctuate seasonally, driven by high-plasticity clay layers and fractured rock seams. A field permeability test (Lefranc/Lugeon) identifies exactly where those water-bearing fractures or permeable lenses occur, so you can design dewatering systems, drainage blankets, or grout curtains before excavation starts. Skipping this step in Birmingham Alabama leads to unexpected seepage during shored excavations, hydrostatic pressure on basement walls, and slope failures in cuts through saprolite.
10⁻⁷ to 10⁻² cm/s (Lefranc); 0.1 to 100 Lugeon units
Reporting standard
ASTM D5092-16, USBR 7300, ICOLD Bulletin 138
Stabilization criterion
Flow variation < 5% over 10 minutes (Lefranc) or < 10% per stage (Lugeon)
Associated technical services
01
Lefranc constant-head test in saprolite & residual soils
Double-packer isolation in NQ boreholes with automated datalogger. Typical test duration: 2–4 hours per zone. Report includes k (cm/s), flow vs. time plots, and stabilization curves.
02
Lugeon multi-stage pressure test in rock
Seven-stage cycle (3-6-10-6-3 bars) with water recovery measurement. Suitable for limestone, dolomite, and fractured schist. Results in Lugeon units and permeability (m/s).
03
Falling-head permeability in low-conductivity formations
For clay-rich saprolite or tight fractures where constant-head cannot stabilize. Uses pressure transducer with 0.1-second logging interval. Detection limit: 10⁻⁷ cm/s.
04
Permeability profiling for dewatering design
We combine Lefranc/Lugeon results with packer-tested transmissivity to estimate inflow rates for excavations, tunnels, and basements in Birmingham Alabama. Delivered as a 3D hydrogeologic model cross-section.
Applicable standards
ASTM D5092-16 (Standard Practice for Design and Installation of Groundwater Monitoring Wells), USBR 7300 (Lugeon Testing Procedure), ASTM D5785-18 (Field Permeability Test in Boreholes Using the Constant-Head Method)
Frequently asked questions
What is the difference between the Lefranc and Lugeon field permeability tests?
The Lefranc test is a constant-head or falling-head injection performed in soils or decomposed rock, measuring hydraulic conductivity (k) in cm/s or m/s. The Lugeon test is a multi-stage pressure injection performed in rock, using 3 to 7 pressure increments and measuring water take in Lugeon units (1 Lugeon = 10⁻⁷ m/s). We choose Lefranc for saprolite and residual soils in Birmingham Alabama, and Lugeon for the fractured limestone and schist of the Valley and Ridge province.
How much does a field permeability test cost in Birmingham Alabama?
A standard field permeability test (Lefranc or Lugeon) in Birmingham Alabama ranges from US$560 to US$1,200 per test zone, depending on borehole depth, packer configuration, and number of stages. Volume discounts apply for multiple zones on the same project.
What standards govern field permeability testing in the United States?
We follow ASTM D5092-16 for well installation and packer setup, ASTM D5785-18 for constant-head field permeability, and USBR 7300 for Lugeon testing. For projects requiring ICOLD compliance, we also reference Bulletin 138. All equipment is calibrated to NIST-traceable standards.
When should I request a Lugeon test instead of a Lefranc test?
Choose the Lugeon test when the borehole encounters intact or fractured rock — limestone, dolomite, schist, or phyllite. In Birmingham Alabama, the Lugeon test is standard for dam foundation investigations, tunnel grouting design, and deep excavation dewatering in the Valley and Ridge limestone belt. The Lefranc test is reserved for saprolite, residual soils, and weathered rock zones above the competent bedrock.
