Dynamic Probes

The Dynamic Probe test is used to determine the resistance of soils in situ to the dynamically driven penetration of a cone. Historically this has been in accordance to B.S. 1377: Part 9 but this has now been superseded by BS EN  1997-2:2007, Eurocode 7 Geotechnical design, ground investigation and testing.

The equipment consists of a 90° cone which may be sacrificial or retained for recovery, a series of extension or driving rods, a torque wrench and a driving device.

There are two type of test: Heavy Dynamic Probing (DPH) and Super Heavy Dynamic Probing (DPSH). The dimensions of the cone and the mass and drop height of the driving weight are different for the two tests as shown below.

The extension rods used in the test are either 0.5 or 1 metre long, manufactured from 35mm diameter heat-treated alloy steel, with graduations marked every 10cm along their length. The rods are flush-jointed and provide a continuous string with a straight axis. The thread form has been specifically designed to resist the driving force. Rods are provided with spanner flats at both ends to enable easy connecting and disconnecting.

The driving device may be a purpose-designed Probing Rig or Automatic Trip Hammer.