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Field Permeability Testing (Lefranc/Lugeon) in Fort Lauderdale

Site investigations you can build on.

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In Fort Lauderdale, the conversation about groundwater starts the moment you break ground. The Biscayne Aquifer sits right under us, and its high transmissivity in the local Miami Limestone and Fort Thompson Formation means standard lab tests on a small sample won't cut it. We run the Lefranc test in soil and weathered rock to get a direct K value right at the depth of your future excavation, and switch to the Lugeon test when we hit competent limestone. CPT testing can screen the profile quickly, but for the actual hydraulic conductivity the regulators need to see, a test pit inspection combined with an in-situ falling-head test gives you defensible, site-specific numbers.

A Lugeon value above 10 in Fort Lauderdale limestone usually means open solution channels. That's not a number you want to discover halfway through an excavation.

Our service areas

Process and scope

A high-rise going up near the New River hit water at six feet during pre-construction. The geotechnical report called for a permeability coefficient to size the dewatering system, and the original lab perm fell apart because the limestone vugs didn't show up in a Shelby tube. Our crew mobilized a track rig and ran three Lugeon stages at the proposed mat foundation elevation. Each stage used a single packer to isolate five-foot intervals, injecting water at constant pressure and recording take every minute. The data we pulled showed a secondary permeability from solution channels that changed the well point layout entirely. For the overlying sands, we ran a Lefranc variable-head test per ASTM D4630, and the combined dataset allowed the dewatering contractor to guarantee drawdown without pulling saltwater intrusion from the Intracoastal. That's the level of detail Fort Lauderdale sites demand—something a generic desktop study simply can't provide.
Field Permeability Testing (Lefranc/Lugeon) in Fort Lauderdale
Technical reference — Fort Lauderdale

Local considerations

The Floridan Aquifer System underlies the Biscayne here, and in eastern Fort Lauderdale salinity is a real constraint. Over-pump a dewatering system without reliable permeability data and the saltwater wedge migrates inland—a problem the South Florida Water Management District takes seriously. We've seen excavations where the contractor assumed a uniform K of 1x10^-4 cm/s based on a grain-size correlation, but the actual Lugeon test revealed a discrete two-foot zone running 100 times faster through a fossil reef lens. When designing cutoff walls, grouting programs, or evaluating base heave in a deep lift station, the difference between a textbook permeability and a field-measured one dictates whether your site stays dry or floods at the worst possible moment.

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Applicable standards

ASTM D4630-19, USBR 7310 Lugeon Test Procedure, FDOT Soils and Foundations Handbook

Typical values

ParameterTypical value
Test MethodLefranc (variable/constant head), Lugeon (packer injection)
Applicable StandardASTM D4630, USBR 7310
Geologic TargetMiami Limestone, Fort Thompson Fm., Pamlico Sand, organic silts
Measurement Range10^-7 to 10^-2 cm/s depending on test type and packer seal
Borehole DiameterNQ to 6-inch, depending on packer size and test zone
Typical Test Depth5 to 80 ft below grade in Fort Lauderdale metro area
Packer TypeSingle pneumatic for Lugeon, open cavity or slotted casing for Lefranc

Common questions

When is a Lugeon test required instead of a Lefranc test in Fort Lauderdale?

The Lugeon test applies when the bearing stratum or excavation bottom is in fractured limestone of the Biscayne Aquifer. It measures hydraulic conductivity of discrete rock intervals under pressure using a packer. A Lefranc test is used in the overlying soil and weathered rock. If the boring log shows more than 30% recovery in limestone with visible vugs, the geotechnical spec should call for Lugeon stages.

How long does a field permeability test program take?

A typical program with two Lefranc tests and three Lugeon stages in one borehole takes one field day for drilling and testing, plus one week for data reduction and the report. More complex sites near the Intracoastal Waterway with tidal influence may require extended monitoring to separate formation response from barometric and tidal effects.

What does a Lefranc or Lugeon test cost in the Fort Lauderdale area?

Location and service area

We serve projects across Fort Lauderdale and surrounding areas.

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