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Sunday, 25 Jun 2017

Geotechnical Tooling (SPT Tools)

Geoprobe® direct push machines outfitted with the Automatic Drop Hammer can be used to perform the Standard Penetration Test (SPT).

SPT BLOW COUNT consists of:

  1. Using a 140 lb. (64 kg) driving mass falling free from a height of 30 in. (762 mm)...
  2. Driving the standard split spoon sampler a distance of 18 in. (457 mm) into the soil, and...
  3. Counting the number of blows (N) to drive the sampler 12 in. (6 in. plus 6 in.) [152 mm plus 152 mm].

Use either a hollow stem auger setup or our 3.25 in. probe rod system.

Hollow Stem Augers
Hollow stem augers are turned to the desired depth with a pilot bit blocking the rod ID. The pilot bit is pulled and a split barrel sampler (split spoon) is lowered. The drop hammer is then placed on top of the rod string and the number of blows to advance the sampler is counted. The pilot bit can then be placed back in the augers and the auger string advanced to the next testing depth.

Geoprobe® 3.25 in. Probe Rods
3.25 in. probe rods are driven to the desired testing depth. The solid drive tip is pulled and a split barrel sampler is lowered. The drop hammer is then placed on top of the rod string and the number of blows to advance the sampler is counted. The solid drive tip can then be placed back in the cutting shoe and the rod string advanced to the next testing depth.

More in this category: « Cone Penetration Test (CPT)