84 / 2025-04-24 12:55:50

Observation of suffusion in pumice sand with non-plastic fines by X-ray CT scanner

In this study, the internal erosion of fine particles (suffusion) in a compacted pumice sand with a
large amount of non-plastic fines was visualized using X-ray CT scanning, and the
microstructural changes that support the tendency of clogging of pores and increasing in shear
strength associated with suffusion were successfully captured. The following conclusions were
obtained: (1) suffusion occurs around large localized pore spaces, and (2) when suffusion
progresses due to water permeation, the fine particles migrated and trapped at the bottleneck of
the pore network, resulting in decrease of hydraulic conductivity due to clogging and increase of
shear strength resistance angle by reinforcement of the soil skeletal structure. These observations
are consistent with the test results obtained in previous studies on shear strength characteristics
of the pumice sand with/without suffusion experience.