Subsurface Explorations

SGS continues to invest in a wide range of exploration equipment and specialized technologies to:
  • Have the right field exploration technique for each project
  • Have the flexibility to respond to unexpected field conditions
  • Efficiently collect reliable data to meet the needs of the projects.

Test Borings

SGS’s fleet of drill rigs allow us to select the right rig for each project

  • Drilling methods include:
    • Solid and hollow stem augers
    • Direct push steel casing
    • Rotary wash borings
    • Bedrock coring
  • Sampling method include:
    • Standard Penetration Testing (SPT)
    • Visual classification of split spoon samples
    • Shear vanes
    • Shelby tubes
  • Groundwater piezometers and sampling wells can be installed with sand pre-packs or constructed in place

Cone Penetration Testing (CPT)

SGS offers CPT exploration technology, which includes the following features:

  • Continuous data acquisition throughout the subsurface profile with a real-time data logging system
  • Interpreted results provide soil type, water table, and soil parameters for engineering design
  • Continuous subsurface profiling and three-dimensional characterization capabilities
  • Seismic testing can be performed at discrete intervals to obtain shear wave data

 

CPT advantages include:

  • Rapid testing and more operator independent than Standard Penetration Testing (SPT)
  • Can delineate discrete low-strength layers, easily missed by SPT
  • Useful for identifying stratigraphic horizons, discontinuous lenses, soft materials, organic materials, liquefaction potential, and landslide shear zones
  • Typically, there is a higher exploration production rate than SPT drilling methods for deep sand and clay deposits
  • Smaller diameter explorations result in less disturbance and no cuttings or spoils

Soil Liners

SGS’s drill rigs are equipped to use soil liner sampling techniques for continuous samples for environmental or soils sampling        

Test Pits

  • Test pits are a practical alternative to test borings for open or undeveloped areas where general soils information is needed
  • Our excavator can conduct test pits to a depth of 10 to 12 feet depending on soil conditions

ASTM Standard Field Methods Performed

  • ASTM D1586: Test Method for Penetration Test SPT (Auto-Hammer)
  • ASTM D1587: Thin-Walled Tube Sampling (Shelby Tube)
  • ASTM D2488: Visual Classification of Soils
  • ASTM D5092: Groundwater Monitoring Wells
  • ASTM D5778: Cone Penetration Testing CPTu
  • ASTM D6151: Hollow Stem Auger Boring for Soil Exploration
  • ASTM D6282: Direct Push for Soil Sampling
  • ASTM D6724: Direct Push Groundwater Monitoring Wells
  • ASTM D6725: Direct Push for Pre-packed Well Installation
  • ASTM G57-06: Soil Resistivity Using the Wenner Four-Electrode Method