DPSH Dynamic Probing Explained: How It Works Under ISO 22476-2

DIAMOND DRILL

Oct 14

1 min read

Dynamic probing is a staple of European ground investigation, and the Super Heavy variant (DPSH) is its workhorse. Specified in ISO 22476-2 and used alongside Eurocode 7 design, it drives a cone into the ground and records resistance continuously with depth.

How it works

A 63.5 kg hammer falls 750 mm onto a string of rods tipped with a 90° cone. The operator counts blows for each 200 mm of penetration (N20). No borehole is drilled and no sample is taken; the blow count profile is the result.

Strengths

Continuous record that reveals thin layers and gradual changes.
Fast and economical: many probes per day, ideal for mapping lateral variability.
Light, mobile equipment for restricted sites.

Limitations

No samples, so soil type must be confirmed by boreholes. Rod friction builds with depth and in cohesive soils unless corrected or controlled, for example by rotating the rods and recording torque. Results are best calibrated against SPT, CPT or borehole data from the same site.

Typical uses

Finding the depth to a competent bearing layer, checking ground variability between boreholes, and screening sites for shallow foundations, embankments and ground improvement verification.