Table 7.21.

Dynamic probing

Probing/dynamic probingMethodApplicationsLimitations
Graphic
  • Steel rod (lead length fitted with a cone shaped driving shoe) driven or pushed into the ground;

  • The number of blows/energy required to advance the rod is recorded;

  • Generally mounted on tracked or wheeled units;

  • Hand-held equipment also available (Mackintosh Probe, TRL Probe);

  • 20–50 m per day.

  • Sites where unrestricted vehicle access can be gained and that are relatively level;

  • Tracked units can be used in sloping or rough terrain or on crest of levees;

  • Simple monitoring wells can be constructed in the completed probe hole;

  • The data from DPL-DPSH tests may be used to derive soil parameters.

  • Soil being tested cannot be identified;

  • Unreliable results in soils containing occasional cobbles or boulders;

  • Limited penetration in very dense and hard formations;

  • Difficult to penetrate near-surface obstructions;

  • Dense gravels can grip onto the rods making extraction difficult;

  • Vibration and noise.

Cost factor: low
Relevance to glacial/periglacial depositsUncertainties in this test associated with the transfer of energy through the rods to the cone tip when penetrating sands and clays, especially where their densities can vary, can seriously restrict the application of the method if used without other methods to confirm lithologies penetrated.