Case Studies

Methodology

Following coring through concrete floor slab, dynamic sampling (windowless sampling) was undertaken with duplex casing through the weathered sandstone (sand) down to bedrock at around three metres below ground level. Rotary coring follow-on to a depth of 7 metres was then undertaken, with SPTs at every metre with the soil and bedrock. At T2-101 triple tube core barrel, with 84mm clear plastic line, was used for rock core recovery with water and foam flush. Standpipes were installed on completion to facilitate gas monitoring.

Challenges

• Several step ups through standard doorways
• Very narrow internal passageways with only 780 mm access width
• No on-road parking and restricted site logistics
• Low headroom within the factory unit
• Drilling in a tight residential setting with apartment blocks on both sides

Client Benefits

• Rig could enter highly restricted internal spaces without demolition, enabling rotary coring exactly where required.
• Significant cost savings on mobilisation relative to a larger rotary rig — windowless sampling alone would not have penetrated bedrock, which was essential for pile design.
• One multi-capable rig completed both dynamic sampling and rotary coring, eliminating the need for multiple rigs and reducing project duration and overall investigation costs.