Cone Penetration Testing (CPT)

Central Alliance’s new cone penetration testing (CPT) crawler rig is capable of tracking through most terrains. Offering a 200 kN push from a stable platform and able to average over 100 m of data acquisition per day, its 1.7 m jack legs ensure a level push on the most precipitous of terrains. The rig includes a wireless remote control, enabling the operator to safely track the rig from outside with maximum visibility.


Piezocone penetration testing (CPTu) has many advantages over traditional site investigation techniques. CPTu has a very high level of accuracy, taking readings from undisturbed, in-situ soil. With an average resolution of 2 cm and capable of averaging over 100 m of testing per day, it is not a surprise that CPTu is being used by the industry more than ever.



Standard CPTu measures four parameters:


  • Cone end resistance (qc)
  • Friction (fs)
  • Pore pressure (u2)
  • Inclination



Central Alliance has conducted Cone Penetration Testing on a variety of sites across the UK, including work on projects with national significance such as HS2.



We provide a variety of probes so can tailor site specific testing suitable for a range of sites.


Our current range includes:

  • 10cm2  CPT Piezocone (Subtraction type)
  • 15cm2 CPT Piezocone (Subtraction type)
  • Ball Shaped Tip for 10cm2 Piezocone
  • Magnetometer



Central Alliance process the CPT Data in house, producing bespoke reports to suit our clients needs. In addition, the processed results are provided in the AGS and Excel formats.



To discuss your project and for availability queries email


Alternatively, fill in a contact form.

There are many geotechnical parameters that can be derived or estimated from CPTu testing.


Reports are provided to show the results of the ground investigation which can be personalised to outline site specific requirements.

A standard CPTu report contains the following information

  • AGS Data
  • Soil behaviour type (SBT)
  • Soil behaviour type index (Ic SBT)
  • Relative density (Dr%)
  • Shear strength (Su kPa)
  • Standard penetration test (SPT) N60
  • Friction angle

Central Alliance can provide an advanced report which can test for and provide any of the following information


  • Permeability (K)
  • Constrained modulus (M)
  • Young’s modulus (Es)
  • Modified soil behaviour type index (IB)
  • Modified soil behaviour type (Mod. SBTn)
  • Peak/effective friction angle
  • Dry unit weight
  • Porosity (n)
  • Soil sensitivity (St)
  • Residual strength ratio
  • Bulk Unit Weight
  • Water content (w%)
  • Void ratio (e)
  • Undrained shear strength ratio
  • Over consolidation ratio (OCR)
  • Shear wave velocity (Vs)
  • State parameter (Ψ)
  • In-situ soil stress ratio (Ko)


We can also offer bespoke packages to include liquefaction assessments and cross-sectional areas of the site.

To download the CPT Datasheet click here: