Geotechnical surveys in UXO suspect areas

T&A performs geotechnical research, depth detection, the determination of the length of sheet piling or the location of anchor rods using a magnetometer cone.

A CPT (Cone Penetration Test) rod with a built-in magnetometer is pressed into the ground in a controlled manner using a CPT truck or CPT platform. Probings can be set up to many tens of meters and can be used on land as well as in water.

Magnetometer CPT

Magnetometer CPT is a magnetic technique that can detect deep ferrous metal objects. Applications include:
  • Detection of deep, large metal objects (UXO).
  • Determining the depth of a sheet pile wall.
  • Locating reinforced piles.
  • Locating anchor rods.
  • Geotechnical probes in suspected area.



The aim of this research was to map a salt dome to a depth of several kilometers using the magnetotelluric measuremen technique. The salt dome is filled with salt water and the top of the salt dome is expected to be located at a depth of approximately 500 meters.

Techniques

Seismic research is usually used to map deeper geology such as salt domes. However, in most cases the depth range and accuracy of magnetotelluric measurements is much more favorable. This technique can replace, but as a rule is used in combination with seismic surveys.

Results

The salt dome has been mapped to a depth of almost two kilometers. The blue colors represent a soil composition with high electrical resistance. The red and yellow colors indicate soil material with a low resistance (and therefore high conductivity). The contour in the figure corresponds to the true position of the salt dome.