Investigation on lateral pressure on a sheet-pile wall with EPS layer supporting an expansive soil slope

A sheet-pile wall was adopted to fortify the expansive soil slope in 4970 Special Railway Line in Dangyang City, China. Due to a water-swelling property of expansive soil, a significant increment of lateral pressure may be induced behind a sheet-pile wall supporting an expansive soil slope. A flexible material of Expandable Polystyrene (EPS) Geofoam can be arranged behind the sheet-pile wall to improve its engineering behavior. Field test and numerical simulation were carried out to investigate the distribution characteristics of lateral pressure on sheet-pile wall with EPS layer supporting an expansive soil slope. The lateral pressure of expansive soil behind the sheet-pile wall with EPS layer subjected to field service condition was obtained. The influence of EPS parameters (i.e. elasticity modulus, thickness and burial depth) on lateral pressure was analyzed. The results show that the EPS with a density of 16 kg/m3 and a thickness of 30 cm can reduce the lateral pressure by 48 % subjected to a concentrated rainfall. The lateral pressure behind the sheet-pile wall without EPS layer shows a peak distribution along the depth, and the lateral pressure of sheet-pile wall with EPS layer distributes approximately uniformly along the depth. The reduction effect of EPS layer on lateral pressure becomes more obvious with an increase in burial depth or thickness of EPS layer. An increase in elastic modulus of EPS decreases the reduction effect of lateral pressure.