Geotechnical Investigations

 

NSN uses a combined approach of the most advanced geophysical methods including Multi-electrode Electrical Resistivity and Cone Penetrometer Testing to provide detailed results for your critical investigations.

Multi-electrode Electrical Resistivity (MER)

The use of our Multi-electrode Electrical Resistivity (MER) survey equipment permits us to rapidly map an entire site in one or two days.  Our results are equivalent to the drilling of several hundred test holes that would take months to complete.  We ground truth our MER profiles with a 20-ton capacity Cone Penetrometer Rig to provide soil densities and lithologic behaviors to our geologic mapping.  

Cone Penetrometer Testing (CPT)

Cone Penetrometer Testing (CPT) is a geophysical method of continuously recording soil densities, pore pressures and sediment behavior types.  CPT produces engineering values that are used in foundation design and is a far superior method to Standard Penetration Testing (SPT).

MER & CPT Together for Superb Soil Investigations!

The graphics above and below show how CPT soundings correlate to an MER transect.

The graphic above is an overlay of seven CPT soundings on an MER profile. The MER identified a depression in the limestone later identified as active sinkhole raveling by the CPT soundings. The limestone surface is visible at the white dashed line. The crosshatched area is where the CPT found loose or raveled soils.

Advantages of CPT over SPT

  • Continuous data collection

  • Modern, reproducible results not dependent on driller or equipment

  • Available pore pressure, seismic, or groundwater sampling tools

  • Environmentally friendly, no drill waste

CPT is very useful for Sinkhole Investigations.

CPT Graphics are very informative.

Back to Electrical Resistivity          Back to Top