Cone Penetration Testing (CPT) provides a rapid, in situ, versatile and safe way to build up an understanding of ground properties.

Our engineers pioneered Cone Penetration Testing in the 1960s and have worked continuously to develop the technology into an internationally recognised capability across a diverse range of applications. 

Used as part of an integrated ground investigation, CPT provides a rapid and cost-effective means of quantifying the geotechnical and geoenvironmental properties of soils and of investigating UXO risk. Capabilities include:

Soil Type & Stratification 

Use of tools such as the standard piezocone and gamma cone - often combined with laboratory testing of samples using the Mostap sampler - enable the identification of ground layers and soil types. This approach is widely used to estimate soil type and map variability with depth across a site.

Geotechnical/dynamic properties

Use of tools such as the cone pressuremeter (CPM), in situ vane and seismic cone enables a range of ground engineering properties to be measured or derived including:

  • Undrained shear strength
  • Soil shear modulus
  • Effective horizontal stress
  • Effective overburden pressure
  • In situ horizontal stress
  • Friction angle (sand)
  • Bearing capacity
  • Relative density
  • Soil deformation

Geoenvironmental 

Tools such as the Ultraviolet Optical Screening Tool (UVOST®), Membrane Interface Probe (MIP), and laser and X-ray fluorescence enable us to investigate contamination in soil and groundwater. Our capability includes the identification and mapping of:

  • Hydrocarbons 
  • Organic compounds 
  • Chlorinated solvents
  • Heavy metals

Hydraulic behaviour 

Use of tools such as the electrical conductivity cone provides valuable information on groundwater quality and ground permeability. We are able to identify:

  • Water composition
  • Temperature
  • Thermal conductivity
  • Ion concentration, type and activity
  • Freshwater/saltwater interfaces

Obstruction and UXO Surveys

We use magnetometer based sensors (Magcone) to map subsurface ferrous objects such as unexploded ordnance. By combining the magnetometer and piezocone, it is possible to investigate UXO and geotechnical properties simultaneously. Our capability includes:

  • Detection of UXO
  • Detection of metallic structures, such as ground anchors
  • Measurement of sheet pile foundation depth

Clients choose to use CPT for a wide range of land and marine applications including:

  • Providing information on ground strata and engineering properties to designers planning foundations for new buildings, structures and highways
  • Geoenvironmental investigations to facilitate the remediation of brownfield sites, where CPT can:
    • Characterise contamination
    • Map the extent of leachate spread, buried obstructions and unexploded ordnance,
    • Determine depth of foundations
  • Geohazard studies, for example the investigation of natural cavities and solution features and man-made features such as shafts and mine workings
  • Quality control checking of earthworks, e.g. compaction testing of road or rail embankments, levees or earth dams
  • Hydrogeological applications including water resource exploration and determining hydraulic behaviour in order to predict its impact on foundations.

Cone penetration testing can provide a wide range of information in suitable soils, delivering large volumes of data to internationally recognised formats at lower cost and with less impact than alternative methods. CPTs have the following features and benefits:

  • Low impact – CPT provides a continuous subsurface picture with less ground disturbance than drilling
  • Highly mobile – CPT can be used in most situations where ground investigation is required. On land, it can be deployed from trucks, tracked vehicles and bespoke vehicles, such as rail wagons. Over water, CPTs can be conducted from vessels, barges and jack-up platforms.
  • In situ measurement – therefore less affected by sample disturbance or stress relief than laboratory-based methods
  • Versatility – we offer modular systems with many types of sensor available, to yield a range of information from a single mobilisation
  • Big data, delivered quickly – with rapid acquisition (>100 m per day), CPT yields thousands of data points to enable reliable site characterisation, and provides digital output that can be transferred in real time
  • Widely recognised – CPT outputs are internationally recognised, meeting most commonly used design codes and quality standards
  • Always evolving – over the course of our 50 years’ CPT development, we have continually worked to improve CPT safety, resilience and technical performance.

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