Development of a new device and statistical analysis

This study deals with suffusion which corresponds to the coupled processes of detachment-transport-filtration of the soil¿s fine fraction between the coarse fraction. A statistical analysis is performed in order to identify the main parameters and to focus on those which can easily be measured on existing structures. By distinguishing gap-graded and widely-graded soils, two correlations are proposed to estimate the soil suffusion susceptibility. By performing suffusion tests with two different-sized devices, the results show the significant effect of specimen size on critical hydraulic gradient and on erosion coefficient. The interpretation of all tests by energy based method permits to avoid this spatial scale effect. With the objective to investigate the influence of flow direction, a new device is designed and realized for the industrial purpose. The new device and associated experimental methodology are validated by the comparison of test results with results of triaxial erodimeter tests and oedopermeameter tests. Finally, tests performed on heterogeneous specimens highlight the influence of flow direction.