A in situ full-scale test was performed in a highway project to use EPS, a new geosynthetic, to decrease the loads on a reinforced concrete culvert beneath embankment, which utilize the high compressibility of EPS to result in a induced trench method. Data had been measuring for one year show that the earth pressures at top and shoulder of the culvert had been decreased to one third and two third of the calculated self weight respectively. It is also can be concluded that the thicker the material is, the smaller the pressure will be decreased.