Penetrometers are tools used to assess the variation of in-situ materials on a site. They come in different types and are used in varying conditions of sub-strata materials. The goal of probing is to create a profile of penetration resistance with depth. This is achieved by using simple equipment to measure the number of blows per unit depth of penetration, which are then plotted as blow-count/depth graphs.
One common type of probing is the Mackintosh Probe, which is a cost-effective tool for determining the thickness of soft deposits like peat. It consists of rods that can be threaded together with barrel connectors and have a driving point at their base and a hand-operated driving hammer at their top. The driving point is streamlined and has a maximum diameter of 27mm. The rods are 1.2m long and 12mm in diameter. When probing with a Mackintosh Probe, the number of blows for each 150mm of penetration is recorded to provide a depth profile.
For stiff clay deposits, an auger or a core tube can be used instead of the driving point. The rods can be rotated clockwise at ground level using a box spanner and tommy bar. To push or pull the tool into or out of the soil, a lifting/driving tool is used. However, the Mackintosh Probe has limitations due to its light hammer weight, which restricts the depth and materials it can penetrate.
