Geotechnical drilling is to gather ground samples of a high quality for a better understanding of the soil structure and allowing for information for structures to be built or working out ground stability. The quality required is normally of higher quality than required for mineral investigation and the sample size is normally of a bigger diameter.

Application Used for very high quality samples contained and sealed for mechanical test to be carried out in a lab dedicated to geotechnical study
Sample quality High quality core sample, sometimes using very high tech sampling systems
Drilling speed Slow progress while allowing for testing being car-ried outft
Hole Depth This can vary from 30/40 metres for structures and up to 1,000 metres for an open cast mine slope sta-bility.
Hole size normally Geotechnical Engineers request a 4” sam-ple diameter
Flexibility There are now systems that allow for In Situ testing, undisturbed sampling as well as contained samples in plastic sleeves that can be sealed.
Cost High, because of the time for testing and the quality required, normally 25% above normal coring cost.
Time The time required to give the quality required varies from project to project depending on what test are required and the quality demanded
Technique There are several methods that can be utilised from Shell & Auger rigs to Multi Purpose rigs utilising angering systems or the Geobor coring system.
Challenges The main challenge is giving the quality demanded which may not correspond to the cost that clients require
Products & Solutions

Drill Structure

Geotechnical sample drilling is carried out with either U4 type sampling system which can be carried out by a Shell&Auger, Auger , or a geotechnical core system

These different systems demand a different type of drilling rig and the methods utilised are following the project requirement

There are several types of drilling is used for giving quality samples, they are as follows:

  • Shelley
  • Hollow Stem Augering
  • S Wireline System

All of these systems can give the quality sample required