Abstract: In this paper,a FEM model for calculating earth pressures behind the abutment with considering the interaction of the earth and the abutment is established, the distribution curves of earth pressures behind the abutment under seasonal fluctuation of temperature are analyzed. With a practical example of a three span continuous concrete bans,two method are proposed and verified:a compressible inclusion of resilient EPS material is used or the EPS block geofoam is used as lightweight fill ,with geosynthetic as reinforcement (geogrid, geotextile or metallic elements). It offers a theoretical basis for design of the abutments.