Methodology
Our DPSH Dynamic Probing follows the principles of Eurocode 7 and BS 5930. Using a 50 kg hammer dropped 500 mm, we drive a 90 mm diameter cone at a rate of 15-30 blows per minute, recording blows per 100 mm penetration. The dynamic cone resistance (qd) is calculated using the formula qd = M g h / (A e), where M is hammer mass, g gravity, h drop height, A cone area, and e penetration per blow. Typical refusal is set at 100 blows per 100 mm or 20 mm penetration per 10 blows. This method is especially effective for profiling up to 8 m depth in granular soils. We complement DPSH with Cone Penetration Test (CPT) for cohesive soil evaluation.
Reference Technical Parameters
| Parameter | Reference Value |
|---|---|
| Hammer Mass | 50 kg |
| Drop Height | 500 mm |
| Cone Diameter | 90 mm |
| Penetration Rate | 15-30 blows/min |
| Max Depth (typical) | 8 m |
Local Considerations — United Kingdom
The United Kingdom's varied geology—from the chalk of southern England to the glacial tills of Scotland—requires adaptable DPSH procedures. In Aberdeen, hard glacial tills demand higher blow counts, while in Ashford, soft alluvial deposits require careful refusal criteria. Our team tailors the testing program to local ground conditions, ensuring compliance with Eurocode 7. For example, in Aylesbury, where clay soils dominate, we adjust the hammer energy to prevent excessive disturbance. Similarly, in Barnsley, we encounter Coal Measures strata that require modified penetration rates. Our nationwide presence allows us to apply these adaptations seamlessly across cities like Basildon and Bangor.
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Applicable Standards
- BS 5930:2015
- Eurocode 7 (EN 1997-2:2007)
- ASTM D1586 (reference for SPT correlation)
- ISSMFE Technical Committee on Penetration Testing
Frequently Asked Questions
What is the difference between DPSH and SPT?
DPSH provides a continuous profile of soil resistance using a cone, while SPT is a discrete test that collects samples. DPSH is faster and ideal for profiling stratigraphy, whereas SPT offers disturbed samples for classification. Both are complementary in geotechnical investigations.
What is the standard procedure for DPSH Dynamic Probing?
Our procedure follows BS 5930: a 50 kg hammer dropped 500 mm drives a 90 mm cone. Blows per 100 mm are recorded until refusal (100 blows/100 mm or 20 mm/10 blows). The dynamic cone resistance is then calculated to assess soil bearing capacity.
How deep can DPSH Dynamic Probing reach?
Typical maximum depth is 8 m, but in favorable conditions (loose sands, soft clays) it can reach 15 m. Refusal in dense gravels or rock may limit depth. Our team assesses site conditions to determine practical depth limits.
How much does DPSH Dynamic Probing cost in the United Kingdom?
Cost varies by depth, accessibility, and number of test points. As a 2026 reference, a single DPSH test to 5 m depth typically ranges from £400 to £800, including mobilization within 50 miles. For a precise quote, please contact our team with project details.