- Predict ground stability responses (e.g. settlement, liquefaction and failure) to imposed loads like foundations, vibrating equipment (e.g. around excavations), earthquakes, trains travelling at high speeds or explosions.
- Measuring the propagation speed of sound using seismic CPT (SCPT), together with the soil density (usually already known), enables calculation of:
- small strain shear modulus & constrained modulus
- elasticity modulus
- Poisson’s ratio
- Determine the depth of regional or perched water tables
A.P. van den Berg’s seismic Cone Pentration Test (SCPT & SCPTu) system adds measurement of both compression and shear wave velocities (Vp, Vs) to the parameters obtained with CPTu (cone tip resistance, sleeve friction and pore pressure).
Elastic soil parameters are determined by measuring the propagation speed of an applied sound wave between two known depths. The seismic module is pushed into the soil while stopping at 1 metre intervals. During the pause in penetration, an shear wave (S wave) or compression wave (P wave) is generated by applying a hammer blow laterally to the end of the hammer beam fixed to the CPT rig and the time required for the wave to reach the seismic sensor is recorded. The time difference between two consecutive seismic tests is a measure for the elastic properties of the soil.
The Icone Seismic Module does this using 3 accelerometers (20Hz – 300Hz) to receive left and right shear waves (S Wave ) as well as compression waves (P Wave).
To increase the speed or accuracy, it is possible to measure at two or even more depths simultaneously by using extra seismic modules, mounted at fixed distances of 0.5 or 1 metres. Furthermore seismic signals from one depth can be stacked in the Ifield software, in order to improve the seismic signal by averaging out the noise.
The Icone Seismic Module is a plug & play extension to the digital Icone data acquisition system and is automatically recognized by Ifield software and Icontrol datalogger. It can be combined with 5, 10 and 15 cm2 Icones or other click-on modules.
When CPT-data are not required, the click-on modules can also be used with a dummy tip instead.
