Gregg Drilling and Testing Canada

Cone Penetration Testing

Offering a full suite of Cone Penetration Testing (CPT) services.

As of 2016 Gregg Drilling and Testing Canada Ltd, became part of the Geotech Group of Companies and offers Cone Penetration Testing (CPT) which involves advancing an instrumented probe (the cone) into the ground/tailings at a steady rate (20 mm/sec) while simultaneously capturing measurements at regular intervals (eg 1.0, 2.0, 2.5, or 5.0 cm) of loads imposed on the probe. Standard measurements include tip resistance, sleeve (shaft) friction, and pore pressures (when in saturated materials). To monitor verticality and data quality, measurements of tilt are also simultaneously recorded at the probe. To achieve the required test depths and facilitate the advance, the probe is connected to a drill string, typically divided in 1 m increments. The advance (or push) is made using dedicated CPT rigs (direct push methods only) or using a push system from a traditional drill rig.

Gregg typically uses a 15cm2 digital system to perform CPT testing. Digital CPT is the standard in the CPT market world-wide as it provides for digital conversion of the sensor measurements within the tool itself and eliminates a potential source of error associated with unresolved non-load cell related changes in resistance that can negatively impact accuracy during the test. Digital systems also allow for the use of additional modules during testing to capture additional in-situ measurements that may be required.

It is Gregg’s experience that a “CPT Project” can include a wide range of required in-situ measurements beyond the standard tip, sleeve, pore pressure and tilt measurements requested from a generic CPT program. It is not uncommon in tailings profiling programs for additional measurement to be required of the cone such as temperature, resistivity (or conductivity), or seismic Shear and Compression wave velocities. Gregg deploys all these modules and has experience in tailings with them.

Gregg uses component-based systems to efficiently and accurately collect this additional data. Note that in addition to the components, Gregg uses a variety of CPT probes to suit the expected site conditions, whether they be very soft (ie: low capacity compression style probes to provide resolution of small loads), or very hard conditions (ie: high capacity subtraction probes to withstand hard conditions and tip pressures up to 100 MPa).