Sand-EPS beads lightweight fill is composed of sand and EPS beads.Based on direct shear tests

the shear strength behavior and influence factors are presented in this paper.The best water content corresponding with the highest shear strength is 10% for this lightweight fill.The shear strength is composed of the following parts:（a） particle sliding;（b） dilatancy;（c） particle breakage;（d） particle rearrangement;and（e） contraction of EPS beads.Shear strength of the lightweight fill decreases with the increasing of the EPS ratio and increases with the increasing of the normal stress.Besides

the internal friction angle of the lightweight fill decreases with the increasing of the EPS ratio

and the cohesion increases with the increasing of the EPS ratio.