Physical modelling and element tests in a table centrifuge
At GeoDelft a small and a large centrifuge stand side by side. The large geocentrifuge is generally used to investigate geotechnical problems related to the interactions between foundations and soils while the small table centrifuge can be used to determine soil properties. This makes a table centrifuge useful in necessary studies prior to large centrifuge tests.
Originally dedicated to clinical applications, a standard table centrifuge has been adapted to fit the needs of geotechnical investigations. In addition to its 4 modified cups diametrially located, sliprings have be mounted in the rotor to make possible the use of sensors in the cup and the transfer of data to the fixed world. Sensors like pressure gauges, electrodes, a displacement sensor could be used successfully in these conditions. It can rotate in a range of 500 to 1800 rpm corresponding to acceleration varying from 50 - 600 times the Earth's gravity.
Because of the small size of table centrifuge arm (the radius varies between 0.11 en 0.19 m) the generated centrifugal acceleration varies strongly with the length of its radius. Numerical programs have been develop to correct this inherent imperfection and eventually the effect of a curved water surface so that geotechnical values can be correctly derived from the measurements.
Up to date, the table geocentrifuge has been implemented in projects like investigations on the consolidation of clay, the settlement of dredge materials under self-weight consolidation, an extensive characterisation of adsorption of contaminant onto soils.
For more information on this subject, please contact: f.m.schenkeveld@geodelft.nl
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