Ground Engineering Solutions

Cone penetration testing

Cone penetration testing (CPT) is advanced scientific ground investigation which involves penetrating cones for meaurement at a constant penetration rate into the soil body in order to measure resistance which is then interpreted into a soil / geotechnical profile. The CPT testing equipment is comprised of a mobile laboratory (usually tracked) which is completely self-contained. The cones provide a continuous trace of data and, thus, a complete profile of the soil body at the probe position. In context, CPT testing is a fast, efficient and versatile form of ground investigation that produces a large volume of high-quality data. In addition, specialist modules allow us to extract samples of soil from any probed depth and we also offer a bespoke plate load testing facility which is a very efficient way to run the test, avoiding the need for cumbersome reaction loads, dial gauges and string lines.

At GES we use innovative & high-quality cone penetration testing equipment in order to provide customers with surety of their data and high-quality results. We offer the following services:

  • Digital piezocone penetration testing
  • Dissipation testing
  • Plate load testing
  • Soil sampling

The basic advantages of cone penetration testing and specifically the piezocone (CPTu) are as follows:

  • Continuous Soil Profile
  • Continuous Porewater Pressure Profile
  • Fast and therefore Economical and Productive
  • Solid theoretical basis in respect of interpretation even in terms of more advanced geotechnical parameters such as shear modulus, overconsolidation ratio or the state parameter

The disadvantages such as high capital cost / requirement for skilled operators / requirement for skilled interpretation are taken care of by us. We invest heavily into our equipment inventory and our site-based staff are well-trained and highly experienced. Our data post-processing is undertaken by experienced geotechnical engineers who are steeped in CPT techniques and understand the subtleties of interpreting the data in order to provide customers with purposeful and actionable information. The ability to feed-in to the over-arching geotechnical design in a meaningful way is something that sets us apart as a ground investigation company.

While CPT is not appropriate in all soil types (for example cobbly gravels / cemented materials and rock), all ground investigations should be undertaken in a geological context such that the correct investigation tool is adopted. This is an important facet of ground investigations generally. The power of cone penetration testing lies in its simplicity and the high repeatability of the test data which is unsurpassed by any other modern ground investigation tool. The ability to measure a continuous trace of porewater pressure measurement means that CPT data is unmatched for soil profiling. The nature of the data measured allows for reliable interpretation of engineering parameters such as soil strength, stiffness, relative density, OCR, at-rest earth pressure & permeability and for direct geotechnical design methods. The high volume of data is also amenable to statistical analyses thereby allowing the epistemic uncertainty to be assessed robustly resulting in higher reliability in the overall geotechnical model.

The particular GES offering is high-end consulting, reporting and geotechnical design off the back of a CPT testing investigation campaign. Rather than just handing over factual data, we can produce high-quality interpretation, spatial & statistical analyses and design thereby offering practical consulting and a more rounded service. This also fits well with our laboratory offering which can provide further particular data as needed. In order to develop effective CPT strategies, the best approach is to engage us early in the project to contribute to the design concept and this will allow us to tailor a CPT testing campaign to establish the data needed to prepare designs. Having the in-house ability to assess bearing capacity, consolidation & settlement and compaction aspects makes our CPT testing offering very powerful.


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