This brief glossary contains some of the most frequently used terms related to CPT/CPTU. These are presented in alphabetical order.
CPT: Cone Prenetration Test or the act of Cone Penetration Testing.
CPTU: Cone Penetration Test with pore water pressure measurement – a piezocone test.
Cone: The part of the Cone penetrometer on which the end bearing is developed.
Cone penetrometer: The assembly containing the cone, friction sleeve, any other sensors and measuring systems, as well as the connections to the push rods.
Cone resistance: The total force acting on the cone, divided by the projected area of the cone.
Corrected cone resistance: The cone resistance corrected for pore water pressure effects.
Corrected sleeve friction: The sleeve friction corrected for pore water pressure effects on the ends of the friction sleeve.
Data acquisition system: The system used to measure and record the measurements made by the cone penetrometer.
Dissipation test: A test when the decay of the pore water pressure is monitored during a pause in penetration.
Filter element: The porous element inserted into the cone penetrometer to allow transmission of the pore water pressure to the pore pressure sensor, while maintaining the correct profile of the cone penetrometer.
Friction ratio: The ratio, expressed as a percentage, of the sleeve friction, to the cone resistance, both measured at the same depth.
Friction reducer: A local enlargement on the push-rod surface, placed at a distance above the cone penetrometer, and provided to reduce the friction on the push rods.
Friction sleeve: The section of the cone penetrometer upon which the sleeve friction is measured.
Normalized cone resistance: The cone resistance expressed in a non dimensional form and taking account of stress changes in situ.
Net cone resistance: The corrected cone resistance minus the vertical total stress.
Net pore pressure: The meausured pore pressure less the equalibrium pore pressure.
Normalized friction ratio: The sleeve friction normalized by the net cone resistance.
Piezocone: A cone penetrometer containing a pore pressure sensors.
Pore pressure: The pore pressure generated during penetration and measured by a pore pressure sensor. Measure on the cone, just behind the cone, or just behind the friction sleeve.
Pore pressure ratio: The net pore pressure normalized with respect to the net cone resistance.
Push rods: The thick walled tubes or rods used for advancing the cone penetrometer.
Thrust machine: The equipment which pushes the cone penetrometer and rods into the ground.
Sleeve friction: The total frictional force acting on the friction sleeve divided by its surface area.