There are several different varieties of dynamic and static penetrometers available, with different types being employed in different sub-strata material situations.
All probing, however, has the same goal: to generate a profile of penetration resistance with depth in order to determine the heterogeneity of in-situ materials on the job site. Probing is done quickly and with basic equipment.
It generates straightforward data in terms of blows per unit depth of penetration, which are typically represented as blow-count/depth graphs.
Mackintosh Probe is one of the most prevalent methods of probing. The Mackintosh prospecting tool is made up of rods with a driving point at the bottom and a light hand-operated driving hammer at the top that may be linked together using barrel connections.
The instrument is a cost-effective way to determine the thickness of soft deposits like peat. The longitudinal portion of the driving point is streamlined, having a maximum diameter of 27mm.
The total weight of the drive hammer is around 4kg. The rods are 1.2 metres long and 12 millimetres in diameter.
The point and rods are driven into the ground with equal blows of the entire drop height allowed from the hammer, and the number of blows for each 150mm of penetration is recorded.
An auger or a core tube can be used instead of a driving point to penetrate small pockets of tough clay. A box spanner and tommy bar can be used to rotate the rods clockwise at ground level.
A lifting/driving tool can be used to push or drag tools into or out of the earth. The depths and materials that the Mackintosh probe may penetrate are limited because to the small hammer weight (Clayton C.R.I., Matthews M.C. and Simons N.E., 1995).
The Mackintosh Probe was developed using Hvorslev’s (1948) ideas for drive rods for sounding and sampling, as well as European Group Subcommittee suggested procedures for static and dynamic sounds (1968).
The probe is made up of a casing that is fastened onto the rod’s bottom end. Each rod is made of HY steel with a diameter of 16mm and a length of 120 cm. The rods are joined by couplings with an outside diameter of 25 mm.
These couplings give the rods lateral support to keep them from buckling during driving. A small hammer, weighing 5 kg and descending vertically through a fixed height of 30 cm along a guide rod, is used to drive. The total number of blows necessary to get the pointer to move.