DEVELOPMENT OF MINIATURE EQUIPMENT FOR A SMALL GEOTECHNICAL CENTRIFUGE

Geotechnical centrifuges are used worldwide to investigate structures whose behaviors are strongly dependent on the mechanical properties of soil. Although centrifuge research is cheaper than real scale testing, it is still expensive. The costs can be reduced significantly if the tests are performed in a small centrifuge. By using miniature equipment and advanced monitoring systems, many geotechnical problems can also be modeled in a small centrifuge. The preparation of a test takes relatively little time, so that the time interval between the idea and the results is short. An additional advantage is that tests with small soil samples can be reproduced very accurately, so that slight modifications of the test models can be visualized. A centrifuge with a diameter of 2 m has been developed at the University of Delft. The design concept was to keep the device as simple as possible and to keep the weight of the samples so low that they could be carried by one person. To enable the performance of a large variety of tests, several miniature devices were developed, such as a sand sprinkler, a two-dimensional loading system, as air supply system, a water supply system, and a vane apparatus. The limitation of space for sensors was neutralized by using image processing techniques to measure the deformation of the soil in flight. Several research projects have been conducted in the centrifuge, for example, shear band analysis and investigations of the sliding behaviors of spudcan foundations, the stabilities of dikes during wave overtopping, blowouts, and the stabilities of embankments during widening.