A recent river crossing project near the Red Deer River required tunneling through saturated silts with less than 15 kPa undrained shear strength—material that flows like toothpaste under pressure. The contractor faced face losses twice before we were brought in to redesign the geotechnical baseline. Soft ground tunneling in central Alberta demands a testing program that captures the transition from glacial lake deposits to the underlying bedrock, because missing that contact zone during a borehole campaign creates a risk profile no contractor should carry. Our laboratory handles the full suite of ASTM and CSA-compatible tests to generate parameters for numerical models, face pressure calculations, and settlement trough predictions. We routinely coordinate with drilling crews operating along the QEII corridor and within Red Deer’s river valley, where the CPT testing data often reveals thin sand lenses that conventional SPT sampling misses entirely, and where grain size analysis of the till matrix helps define the abrasivity index for cutterhead selection.
The contact between soft glaciolacustrine silt and Paskapoo shale in Red Deer can shift the required face pressure by 80 kPa over less than two meters of vertical advance.
