A centrifuge modelling setup for dewatering, rewetting, and characterising soil deposits

Dewatering in soils serves various purposes in the field of geotechnical engineering as well as other disciplines. In geotechnical engineering, dewatering is effective for improving stability, reducing settlements, and limiting seepage of contaminated pore fluid. This study details the development of an experimental setup that enables dewatering and rewetting soil deposits in-flight in a geotechnical centrifuge while the pore pressures/suctions and moisture contents are measured. Cone penetration tests and shear wave velocity measurements are also used to characterise the material in-flight. Detailed discussion is provided regarding the construction of the tensiometers and calibration of the moisture content probes. Tests are performed on two coal combustion products (CCPs) to exemplify the capabilities of the equipment. Illustrative test results provide time histories and profiles of soil suction and water content at different depths, agreeing well with measurements from laboratory soil water retention curves. The results also show that dewatering of the CCP deposits leads to significant increases in strength and stiffness and, after subsequent rewetting, the material maintains a permanent increase in stiffness. The developed system enables an economical and reliable study of the impacts related to dewatering and rewetting cycles to fulfil research purposes in a broad range of engineering disciplines.