Specialist Magnetometer Testing: Intrusive UXO Surveys

Equipped with magnetometer sensors, our Magnetometer CPTs are adept at detecting iron-containing objects beneath the subsurface. The measuring principle of the magnetometer is based on the detection of magnetic irregularities in the earth’s magnetic field caused by iron-containing objects.

Whether we are mapping UXO or determining the position of metallic structures like retaining or tieback anchors, our magnetometer tests ensure precision. This advanced technology is instrumental in identifying magnetic irregularities, particularly vital for pinpointing UXO during intrusive surveys.

Our cones play a crucial role in mapping objects such as UXO and can be utilised alongside our combination piezocone. This allows for the simultaneous investigation of geotechnical engineering properties, offering you both cost and time-saving benefits.

When used for intrusive unexploded ordnance clearance, our operatives monitor the magnetometer readings on site. Should any significant anomalies be detected in the output our operations team will discuss the next step in the UXO risk mitigation process with the assistance of a third-party UXO specialist. A full UXO clearance report can be produced on completion of works.

The magnetometer can detect objects within a maximum radius of 2 meters dependent on the size of the disturbance and soil profile and is suitable for:

• Detection of UXO.
• Measurement of the length of sheet pile foundations.
• Determination of the position of metallic retaining or tieback anchors.
• Our rigs can survey either single pile positions or clusters for deeper site excavation works – surveying to depths of up to ~25m.
• Suitable on brownfield sites or sites where the presence of made ground may preclude a non-intrusive UXO method. Surveys to significantly greater depths are achievable compared to non-intrusive mitigation measures.

We carry out CPT using crawler units fitted with polyurethane track pads to protect sensitive surfaces and our CPT equipment includes:

• Electric friction cones and piezocones – for assessment of soil stratigraphy and strength
• characteristics.
• Dissipation tests can be carried out to estimate consolidation properties.
• Seismic cone – for measurement of shear wave velocity profile and determination of shear
• modulus.
• MOSTAP sampling – for recovery of undisturbed samples.
• Vane testing – for strength measurement of softer clays.
• Push-in pressuremeters