The packer assembly slides down the borehole first. A single or double inflatable packer seals off the test section at the desired depth. In Saint-Jerome, we run these Lefranc and Lugeon tests right on your site, whether you're up on the morainal deposits near the Rivière du Nord or down in the compact till east of Highway 15. The Lugeon method injects water under pressure into the rock mass to measure joint permeability. The Lefranc method handles the granular overburden, giving you a direct measurement of hydraulic conductivity without disturbing the natural flow regime. For fractured bedrock typical of the Laurentian Shield, we often pair the Lugeon test with a downhole seismic refraction survey to correlate fracture density with wave velocity before any excavation begins.
A lab permeability test on a 50 mm sample tells you nothing about the water flowing through a 2-meter fractured zone. Field tests measure the rock mass, not a specimen.
Process and scope
Site-specific factors
We've seen too many Saint-Jerome projects where the geotechnical report had great lab data but zero field permeability values. Then the excavation hits a water-bearing fracture zone and the dewatering plan collapses. The cost of redesign and delay is brutal compared to running two or three Lugeon tests during the initial site investigation. Another quiet risk is assuming the overburden is homogeneous. A Lefranc test in a sandy lens might give k = 1×10⁻³ cm/s. Two meters away in a silty layer, it could be two orders of magnitude lower. Without spatial coverage, your dewatering design is guesswork. The Quebec Ministry of Environment requires realistic inflow estimates for dewatering permits; field permeability data is the only defensible basis for those numbers.
Reference standards
NBCC (National Building Code of Canada) for foundation water management, CSA A23.3 for concrete structures exposed to groundwater, ASTM D4630 for rock permeability testing (Lugeon), ASTM D6391 for field hydraulic conductivity (Lefranc)
Other technical services
Lugeon packer testing in bedrock
Staged pressure tests in NQ or HQ boreholes. We follow ISRM suggested methods, reporting Lugeon values and interpreted hydraulic conductivity for each tested interval.
Lefranc variable-head testing in soils
In-situ measurement of hydraulic conductivity in granular and silty overburden. Suitable for dewatering design, infiltration studies, and environmental site assessments.
Dewatering feasibility assessment
We combine field permeability data with your excavation geometry to estimate steady-state inflows, helping you size pumps and meet MELCC permit requirements.
Typical parameters
Frequently asked questions
What is the cost of a field permeability test in Saint-Jerome?
For a single Lefranc or Lugeon test at one depth interval, budget roughly CA$850 to CA$1,630. The final cost depends on access, borehole availability, and the number of test intervals. We provide a fixed quote after reviewing your site conditions.
How many Lugeon tests do I need for my Saint-Jerome project?
It depends on the rock mass variability. In the fractured Laurentian Shield rock common around Saint-Jerome, we recommend at least one test per 5 to 10 meters of borehole depth, with additional tests at zones of high fracture density or where core recovery drops.
How long does a Lefranc test take on site?
A variable-head Lefranc test in granular soils typically takes 30 to 60 minutes per interval once the borehole is ready. The falling-head phase itself may be quick in permeable sands, but we run multiple repeats to confirm steady values.
Can you run Lugeon tests in existing water wells?
Yes, if the well is uncased in the test section and the diameter accommodates our packer assembly. It's a practical way to get permeability data without drilling a new borehole, especially in established Saint-Jerome developments.