Ground testing methods
Our engineers pioneered ground testing methods using 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:
Using ground testing methods to determine soil type and 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 and 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
Aquisense™ Hydraulic properties analysis
Aquisense™ provides valuable information on ground(water) quality and hydraulic properties of the soil. Its real-time measurements are used to identify permeable soil zones, which are critical for engineering design and can be selected and targeted for a Mini Pumping Test (MPT®). The MPT® provides absolute and undisturbed measurement of the horizontal conductivity and is used to calibrate the continuous relative permeability profile from the hydraulic profiling tool (HPT). Measurements are carried out in situ without recovery or rerun of the tool. Additionally, the vertical hydraulic conductivity can be determined with the so-called Anisotropic Mini Pumping Test (AMPT®)
Aquisense™ delivers absolute horizontal permeability profiles using the HPT-(A) MPT® technology with a single push ground probe, optimising and even removing the need for costly slug and pump techniques. Aquisense™ data can contribute to a high fidelity digital ground model to support better groundwater management decisions.
Our capabilities include the identification and mapping of:
- Relative and absolute hydraulic conductivity
- Anisotropy and storativity of permeable layers
- Electric conductivity of the soil
- Freshwater/salinewater interface
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 tests 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. Cone penetration tests have the following benefits:
- Low impact – Cone penetration tests provides a continuous subsurface picture with less ground disturbance than drilling
- Highly mobile – Cone penetration tests 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, Cone penetration tests 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 – Cone penetration tests 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 Cone penetration tests safety, resilience and technical performance.