The most common misstep we see on Moncton sites is relying on isolated borehole data to characterize a site that sits on interlayered glaciomarine silts and stiff clay till. A project off Wheeler Boulevard might show competent bearing at 3 meters in one SPT boring, while a second hole 20 meters away hits a compressible silt pocket that goes undetected until excavation reveals differential settlement. The Spt Drilling approach gives you data points every 1.5 meters; what it misses between those intervals can become the reason a foundation underperforms. Cone Penetration Testing fills that gap. A CPT rig pushes an instrumented cone continuously through the subsurface at a constant 2 cm/s, recording tip resistance, sleeve friction, and pore pressure every few centimeters. The result is a near-continuous profile that catches thin sand seams, softening zones, and transitions that standard drilling overlooks, which matters enormously when you are working within the post-glacial stratigraphy that defines Greater Moncton.
A continuous CPT trace through Moncton's glaciomarine sequence reveals thin drainage layers that standard SPT sampling misses, and those layers control settlement rate predictions.
Technical details of the service in Moncton
Demonstration video
Critical ground factors in Moncton
The contrast between Moncton's dry summer crust and its saturated spring conditions cannot be overstated. From April through late May, the upper two meters of glaciomarine silt can hold near-surface groundwater perched above a desiccated clay layer, creating a false strength reading if CPT data is collected during a dry week and extrapolated to post-construction conditions when foundations sit in fully recharged soil. We have seen cone tip resistances drop by 30 to 40 percent in the same stratum after a major rain event, simply because matric suction was masking the true effective stress. That seasonal variability makes a strong case for coupling CPT with In-Situ Permeability testing to determine how quickly pore pressures recover after disturbance. For sites on the Dieppe side where fill placement over former estuarine mud has left compressible layers at 5 to 8 meters depth, the dissipation test data becomes the single most critical input to the settlement analysis, because it reveals whether excess pore pressures from construction loading will dissipate in weeks or in years.
Our services
Cone penetration testing in Moncton works best when paired with complementary investigation methods that address its limitations. CPT gives you continuous stratigraphy and geotechnical parameters derived from empirical correlations, but it cannot retrieve physical samples for visual classification or laboratory testing. The services we coordinate alongside CPT are selected to provide the missing pieces.
Piezocone with Pore Pressure Dissipation (CPTu)
Full piezocone deployment recording qc, fs, and u2 simultaneously. Dissipation tests staged at depths where fine-grained soils govern settlement rate. Data processed through Robertson (1990) SBT classification and used to estimate equivalent SPT N60 values via the Jefferies & Davies (1993) correlation for Canadian soils. Particularly valuable in the Moncton basin where Champlain Sea clays show sensitivity values between 4 and 8 that influence how much strength may be lost during pile driving or excavation unloading.
Seismic CPT (SCPT) for Shear Wave Velocity
A seismic module added to the CPT string measures downhole shear wave velocity at 1-meter intervals, generating a continuous Vs profile that feeds directly into NBCC 2020 site classification (Classes C through E are typical for Moncton). This eliminates the need for a separate MASW survey on sites where CPT is already planned, and the combined qc-Vs dataset enables liquefaction screening via the Robertson & Wride (1998) method without requiring SPT blow counts.
Common questions
What depth can CPT typically reach in Moncton's glaciomarine soils?
In the fine-grained Champlain Sea silts and clays that dominate the central Moncton basin and the lower Dieppe area, a 20-tonne CPT truck can routinely push to 20–25 meters before reaching rod capacity. In the northwestern part of the city where the Lutesville Till contains abundant granite cobbles and boulders, refusal often occurs between 6 and 12 meters. We assess refusal risk during the planning stage by reviewing surficial geology maps and any prior borehole logs from the New Brunswick Department of Transportation and Infrastructure, and we specify a heavier push system when till is anticipated.
How does CPT compare to SPT for liquefaction assessment in the Moncton area?
CPT provides a continuous record of tip resistance and sleeve friction that is inherently more repeatable than SPT blow counts, which can be affected by drill rod energy transfer, borehole disturbance, and operator technique. For the loose sandy silts found in the floodplain deposits near the Petitcodiac River, the Robertson & Wride (1998) CPT-based liquefaction triggering method uses normalized tip resistance and friction ratio to calculate the cyclic resistance ratio directly. This avoids the energy correction uncertainties that affect SPT-based methods, and the continuous profile means we do not miss thin liquefiable seams between sampling intervals, which is critical because a 150-mm sand seam can still generate enough excess pore pressure to cause surface manifestation.
What does a CPT investigation in Moncton typically cost?
For a standard CPT sounding with tip resistance, sleeve friction, and inclinometer data, budget between CA$240 and CA$350 per meter of penetration, with a minimum mobilization charge that typically covers the first 10–15 meters. Piezocone (CPTu) with pore pressure measurement adds a surcharge per sounding due to the saturated filter element and more complex data acquisition. Seismic CPT (SCPT) carries a further increment per test interval because it requires a separate seismic source and geophone module. The total project cost depends on the number of soundings, whether dissipation tests are staged at multiple depths, and the site accessibility: tight urban sites in downtown Moncton with limited rig access may incur additional setup time.
Can CPT data replace soil borings for a foundation design submission in New Brunswick?
CPT can replace a significant portion of the boring program when combined with at least one or two sampled boreholes to ground-truth the soil behavior type classification. Most geotechnical engineers in New Brunswick will accept a site investigation package that includes CPT soundings for continuous profiling plus targeted SPT boreholes with Shelby tube samples for Atterberg limits, grain size distribution, and consolidation testing. The key is that the CPT data must be correlated to laboratory results from the same site to validate the SBTn classification. For NBCC 2020 Part 4 compliance, the investigation must provide enough information to characterize both strength and compressibility across the foundation influence zone, and a well-planned CPT program with complementary sampling does exactly that.