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The Mackintosh Probe is a lightweight, portable in-situ testing system designed to measure soil bearing capacity at depth — quickly, accurately, and without heavy plant or equipment. Operating to BS1377, the Mackintosh Probe is the most widely used dynamic penetration test for determining the N-value (blows per 300mm) of different soil layers to depths of up to 18 metres.

The test is particularly effective in soft, loose, or variable soils including peat, fill, and alluvial deposits, where conventional investigation methods can be difficult or costly. Results are expressed as the number of hammer blows required to drive the cone 300mm, providing a direct indication of relative soil density and bearing capacity at each depth interval.

How It Works

A 25mm diameter, 60° hardened steel cone is attached to the bottom of a series of 15mm diameter steel rods (each 1.20m long). The rods are driven into the ground by dropping a 4.5kg hammer freely through a height of 300mm onto an anvil. The number of blows required to achieve each 300mm of penetration is recorded, building a continuous soil profile from surface to the required investigation depth.

Kit Contents

• Penetration rods (1,200mm / 47¼" each) — 13 nos
• Couplings — 13 nos
• Pipe wrenches — 2 nos
• Penetration cone (25mm, 60°) — 2 nos
• Hammer nuts — 2 nos
• Hammer (4.5kg) — 1 no
• Lifting handle — 1 no
• Heavy duty carrying case — 1 no

Technical Specification

• Standard: BS1377
• Model: MPA-1
• Rod diameter: 15mm
• Rod length: 1,200mm (47¼") per section
• Cone diameter: 25mm
• Cone angle: 60°
• Hammer mass: 4.5kg
• Hammer drop height: 300mm
• Maximum investigation depth: 18 metres (with standard 13-rod kit)

Applications

• Soil bearing capacity assessment for shallow foundations
• Investigation of soft ground and peat deposits
• Fill and embankment investigation
• Rapid site characterisation prior to detailed investigation
• Comparison of soil conditions across a site

The Mackintosh Probe kit is supplied in a heavy duty carrying case for ease of transport to site. All components are manufactured to BS1377 requirements.

For further information or to discuss your site investigation requirements, contact us at hello@geositesupply.com.