Cone Penetration Testing (CPT)

Our Piezocones are digital and measure the four standard parameters: cone tip resistance (qc), sleeve friction (fs), pore water pressure (u) and inclination (Ix/y).

The cone is mechanically 75% stronger than its analog predecessor and at the same time more accurate, more reliable and easier to maintain – and the calibration data is stored in the cone itself which makes the setup process quick and efficient.

Our P10-CFPTxy and P15-CFPTxy Piezocones are suitable for CPT with or without measurement of pore pressure simply by mounting a different conical tip and making changes to the software parameters that are recorded.

We also offer the possibility to replace the conical tip with a ‘Ball tip’ or ‘T-bar tip’.

Ball Tip

Some soils are so soft that the Piezocone encounters insufficient resistance to perform a CPT test. For these kinds of special situations, the 100 mm large ‘Ball Tip’ at the front of the cone experiences considerably more resistance during the CPT test to accurately measure the bearing capacity of extremely soft soils.

T-Bar Tip

Underground cables and pipelines add additional load on the subsoil and it tends to sag where it’s less supported. In order to assess whether this risk of sagging exists on a cable or pipeline route, we offer a CPT test with a ‘T-bar Tip’ which has been developed specifically for this type of situation.

Dissipation tests measure the decay of pore water pressure in ground layers over a specified amount of time, and are used to calculate parameters such as the coefficient of consolidation in the layers.

For a Dissipation test, the Cone Penetration Test is paused when the cone has generated an excess pore pressure. During this phase, any excess pore pressure generated around the cone will start to dissipate, and the pressure decay readings are recorded via a filter element.

The rate of dissipation depends upon the coefficient of consolidation, which in turn, depends on the compressibility of the ground layers.

We then measure the time it takes for this excess pore pressure to drop back down to the hydrostatic pore pressure, and the rate of this dissipation allows us to calculate the coefficient of consolidation in the ground layers.

Dissipation tests are useful in helping understand how the ground layers will behave with heavy surface loads.

Gamma Cone tests are commonly used for chalk solution investigations as it can be difficult to tell the difference between clay infill material, and highly weathered chalk – due to its similar properties when the cone penetrates the ground.

The Gamma Cone obtains high gamma readings in the clay material due to the presence of elements such as potassium and very low readings in the chalk.

Using a Gamma Cone in conjunction with other parameters such as pore pressure (Piezocone) allows us to accurately determine the chalk interface.

Seismic Cone, In-situ Vane & Full Displacement Pressuremeter testing enables a range of ground engineering properties to be measured and calculated.

The cones can be configured to measure ‘s’ and ‘p’ waves and measure the seismic velocity of the ground from sources that are based on the surface, and the measurements taken can be used for analysis of the small strain stiffness in the ground.

Undrained shear strength such as Soil shear modulus, Effective horizontal stress, Effective overburden pressure, In-situ horizontal stress, Friction angle (Sand), Bearing capacity, Relative density & Soil deformation can all be accurately measured.

Ultraviolet Optical Screening Tool (UVOST®), Membrane Interface Probe (MIP) & Laser and X-ray Fluorescence testing – used in combination with CPT as an in-situ tool for the screening – enables us to investigate contamination in the soil and groundwater.

These tests provide identification and mapping of Hydrocarbons, Organic compounds, Chlorinated solvents & Heavy metals.

PAH (Polycyclic Aromatic Hydrocarbons) fluoresce if they are excited by light of a specific wavelength, and this excitation leads to light emission in a certain wavelength range – which is called ‘Fluorescence’.

As PAH occur in all types of oil, the UVOST® is able to detect contamination caused by oil derived hydrocarbons – i.e. jet fuel, diesel, petrol, mineral oil, tar, creosote etc.

The Electrical Conductivity Cone test measures the conductivity of the soil while performing a standard CPT, and the results can be used for analysing salinity and the detection of pollutants – and provides valuable information on groundwater quality and ground permeability.

We are able to identify Water composition, Temperature, Thermal conductivity, Ion concentration, Type & activity and Freshwater / Saltwater interfaces.