Microscopic Distribution of Bentonite in Pore Spaces of Sand after Infiltration of Stabilizing Solution with Different Concentrations

Abstract In the earth drilling method, ground excavation is performed using stabilizing solution made of bentonite. The solution infiltrates into the excavated ground and forms a mud film on the trench wall, contributing to the stability of the trench wall. Previous studies have focused on the macroscopic aspects of the mud film formation, mainly by observing whether or not a mud film is formed through laboratory model experiments, leaving the mechanism of mud film formation only conceptually understood. In this study, infiltration tests of the stabilizing solution with different concentrations of bentonite were performed, and pore spaces of sand was observed using an X-ray micro CT. It was found that the permeability of the sand was greatly affected not only by the mud film, but also by the clogging of the bentonite in pore spaces of the sand.