The role of clay content on the response of railway track foundations during free-to-drain cyclic changes in principal stress rotation

Abstract

Abstract This paper investigates the role of clay content on the response of railway track foundation materials during free-to-drain cyclic changes in principal stress rotation. Four sand clay mixes typical of an in situ railway track foundation were investigated, with clay contents varying from 7% to 24%. It was found that increasing the clay content from 7% to 24%, reduced the volumetric contraction of the mixes during cyclic shear stress increases below a cyclic shear threshold. Volumetric strain reduced with both increasing intergranular and global void ratios. Non linear regression analysis showed generally high correlations between volumetric strain and both intergranular and global void ratios, with the relationship between volumetric strain and intergranular void ratio showing less scatter.