Geotechnical Geophysics

• Determine depth to bedrock (GPR, seismic, resistivity imaging)
• Map geological structure, locate faults, fracture zones
• Locate and map cavities, tomos, buried kauri logs
• Borehole Geophysics
  (televiewer, borehole camera etc)



Equipment Resources
• GSSI SIR-3000, SIR-10 GPR systems with 35MHz, 200MHz, 400MHz, 500MHz, 1.5GHz antenna
• GSM-19 gradiometer / magnetometer (0.02nT resolution)
• AGI STING Multi electrode resistivity imaging system
• Geonics EM-34 XL (0-30m depth range)
• Omnistar differential GPS

Engineering and non-destructive testing (NDT)

 

Geophysical techniques such as GPR are non-destructive methods which can be used to evaluate engineering structures such as roads, bridges and airport runways.

Large areas can be scanned quickly and accurately using GPR in combination with a digital survey wheel and Differential GPS. After data processing, a 3D image can be generated to give the client an in-depth view of the structure and identify defects.

 

What can we do ?

• Testing for manufacturing defects in concrete using high-frequency GPR
• cavity detection in structures
• moisture detection (qualitative only)
• corrosion detection
• delamination
• defects in concrete pipelines
• presence of reinforcing, depth and spacing

 

Types of structure

• Roads
• Bridges
• Airport runways
• Tunnels
• Historic buildings (masonry / wood structures)
• Vertical walls (eg dams)
• Concrete pipelines (inside and outside)

 

Concrete inspection using Ground Penetrating Radar (GPR)

 

GPR can be used to measure:
• Construction type
• Depth to Reinforcing
• Deterioration of reinforcing (relative)
• Thickness of concrete
• Cracks, slumping, delamination

Raw GPR image



Processed version of image



Processing to enhance reinforcing



Interpretation

We can even get to those 'hard to reach' bits..