A foundation dig on Water Street hit refusal at two meters. The contractor called it bedrock. It was a glacial erratic the size of a pickup truck. That kind of surprise is common in St. John's. The city sits on a rumpled blanket of glacial till, draped over shale and sandstone, with pockets of marine clay tucked into the harbour basin. A standard borehole tells you one story at one point. A CPT test tells you the continuous story between those points. We run a 20-tonne rig through the tight streets of downtown and up the slopes of Shea Heights without missing a beat. The cone reads tip resistance, sleeve friction, and pore pressure simultaneously, giving you a stratigraphic profile that catches every lens, every transition.
When the till is dense and the schedule is tight, combining CPT with SPT drilling gives you the best of both worlds: continuous data plus a physical sample at the critical depth.
Twenty centimeters of continuous data beats a grab sample every two meters when the geology changes that fast.
