GRIZZLY DPSH Principles of Operation

GRIZZLY Dynamic Probing Super Heavy (DPSH) Travelling Mode The GRIZZLY Dynamic Probing Super Heavy (DPSH) is a rig designed for compaction control and soil investigation to provide a measure of the in-situ strength of fine- grained and granular subgrades, base and subbase materials, and weakly cemented materials. The constant energy for this heavyweight dynamic cone penetrometer is a 63.5 kg weight that is raised to a height 760 mm and then dropped, driving the cone into the soil or other material being tested. The cone area is 20 cm² for both fixed or lost cones (sacrificial cones) and the 1m rods are 32 mm diameter. The GRIZZLY is supplied with five 1m rods but depths of 10-15m or more can be achieved, depending on the soil type. Soil grain size can be up to 150 mm.

DPSH Dynamic Probing Super Heavy Integrated Hydraulic Rod ExtractorFor dynamic probing, the depth of penetration is measured after each blow with the penetration rate expressed in mm per blow. The hammering frequency is adjustable from 20 to 30 strokes/min. The hammer is hydraulic operated allowing upwards and downwards movement and pole tilting adjustment allowing for slopes or inclinations of 25° longitudinally and 20° laterally.

The onboard data processing software enables direct reading of the penetrogram so that decisions can be made immediately. The digital strokes are displayed on screen in real time and testing locations are accurately recorded using the embedded GPS system with links to Google Earth.

For compaction control, the measurement of the driving depth in mm per strike is compared to a database based on the type of soil (soil classification), its water content and the required compaction quality (%OPN or OPM). Anomalies calculation is done automatically with the embedded software. For soil investigation, the penetrogram can be drawn according to the dynamic resistance (MPa) and the number of blows every 10 or 20 cm (N10 or N20). A geological cross-section (database available) can be associated with the penetrogram.The onboard software has an inbuilt automatic stop sysDemountable GRIZZLY DPSH Onboard Data Acquisition and Analysis Software Casetem both for depth and for the addition of rods.

The Rod Extractor is integrated into the hammer with a powerful hydraulic extraction strength of 11 tons.

The petrol engine self-propelled rig weights approx 800kg complete with hydraulic hammer and is equipped with tracks for tackling difficult terrain. The GRIZZLY DPSH rig has good stability on hilly terrains because of its low centre of gravity. The width of the tracks does not exceed the maximum width of the machine.

The use of GRIZZLY DPSH for dynamic probing complies with several standards and regulatory standards including:

  • NF P94-063 – Compaction quality control – Constant energy dynamic penetrometer method.
  • NF P94-115 – Soil investigation and trials – Type B sounding with a dynamic cone penetrometer.
  • EN ISO 22476-2 – Geotechnical engineering – Field testing – Part 2: Dynamic probing – DPSH-B (Dynamic Probing Super Heavy: test representing the upper end of the mass range of dynamic equipment)
 DPSH Grizzly Dynamic Probing Super Heavy constant energy heavyweight dynamic cone penetrometer DPSH Grizzly Dynamic Probing Super Heavy constant energy heavyweight dynamic cone penetrometer
Dimensions: L 1.86m x W 0.89m x H folded 1.24m
Weight: Approx 800 kg. Max Working Height 3.13m
GRIZZLY can easily be loaded in a
commercial vehicle.
 DPSH Grizzly Dynamic Probing Super Heavy constant energy heavyweight dynamic cone penetrometer DPSH Grizzly Dynamic Probing Super Heavy constant energy heavyweight dynamic cone penetrometer DPSH Grizzly Dynamic Probing Super Heavy constant energy heavyweight dynamic cone penetrometer
Integrated Rod ExtractorTiltingWaterproof touch screen