Centara Ltd


"Your solution is on our radar"

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Geophysical / Geotechnical Solutions

Specialist Geophysical Services using Ground Penetrating Radar (GPR)

As well as utility mapping our specialist GPR can be utilised for other applications. Knowledge and mapping of the subsurface is conducted using a wide range of geophysical methods. The most reliable and cost-effective of these methods for high resolution mapping of shallow depths of a few tens of meters, is by far, Ground Penetrating Radar (or Ground Probing Radar).

GPR methods use electromagnetic waves to image the subsurface, by transmitting radar pulses into the ground and receiving a returned signal from interfaces below. Radar returns are gathered to an image, which can be analysed for its derived electrical properties and subsurface characteristics. Common applications which Centara can provide include:

  • Concrete and rebar imaging and inspection.
  • Sinkholes and void location.
  • Tank (UST) and drum location.
  • Geology (bedrock) and geologic hazards.
  • Landfills and burial trenches.
  • Unmarked cemetery and grave location.
  • Archaeological studies.
  • Compaction and void location on highways including utility reinstatements.
  • Oil and Water leakage detection and location.
  • Unexploded ordnance (UXO).

Geotechnical and Geoenvironmental

We are experienced in a large range of geotechnical investigations ranging from small-scale residential developments to large commercial and industrial developments; these investigations are essential to assess the physical properties of the underlying soils and rock. We have experience in numerous geotechnical areas including road and railway work, pipelines, sewers, earthworks projects, slope stability, tunnelling and treatment and assessment of shallow mine workings.

These services include:

  • Cable percussion drilling.
  • Mini percussive drilling, window sampling and dynamic probing.
  • Window sampling using hand held equipment.
  • Concrete coring.
  • Rotary drilling (coring and open-hole).
  • Trial pitting.
  • In-situ testing.
  • GPR Foundation Surveys.
  • Hand excavation to locate building foundations.
  • Post site works monitoring and sampling.

With increased brownfield developments and pressure to provide cost effective solutions it is important to carry out a thorough geotechnical and geoenvironmental investigation to ensure the best practical solution is adopted. With our own drilling rigs and crews we can maintain direct control on the investigation to ensure accurate and reliable results are achieved. Geotechnical and geoenvironmeantal investigations can be undertaken in conjunction with each other to reduce costs.

In addition to drilling and trial pitting a number of insitu tests can be undertaken on site including, but not limited to California Bearing Ratio (CBR) testing, dynamic probing, plate bearing tests and mexeprobe tests.

Environmental Investigations

We also offer a wide variety of environmental services. Environmental assessments are often required by the Local Authority as part of obtaining planning permission. This process begins with a desk study where the site’s history is examined; many sites have had past industrial uses dating back to the 1850s or even earlier, and some of these uses may have contaminated the ground. The desk study also considers whether there are rivers or groundwater resources nearby that could be polluted by contamination in the ground. Using the desk study information, an environmental investigation can be planned to determine the extent of any potential contamination using techniques such as trial pitting or drilling. Samples are recovered from the exploratory holes and submitted for chemical testing at an MCERTS-accredited laboratory.

Monitoring wells are often installed during the investigation to allow groundwater samples to be recovered. Current guidance also requires the monitoring of gases such as methane on many sites. Using gas data from the monitoring wells, details of suitable protection measures can be designed (such as gas membranes in the floor) for new developments.

Read about Vacuum Excavation here...