MAHDI MOHAMAD JAFARI - M.A student in field of soil and foundation , school of engineering , central Tehran branch , Islamic Azad university , Tehran , Iran

In the study , the properties of shear resistance of geofoam-sand mixture and sand have been investigated by the direct shear experiment. The direct shear experiments have been performed with three vertical stresses ( 50 , 100 , 150 kpa) in form of 10*10 cm. Geofoam-sand mixtures have been remade with 0.2 , 0.4 and 0.6 weight percent of geofoam and two sizes of granules ( fine passing through sieve 10 and coarse remaining on sieve 4). Results from the experiments show that friction angle , dilatation amount decrease in sand and pseudo- cohesion increases in geofoam-sand mixture when weight percent of geofoam is increased. By increasing the vertical stress in this mixture ( with same weight percent of geofoam) , the shear resistance is increased and dilatation is c decreased. The coarse geofoam-sand mixture ( in a same weight percent of geofoam) has less shear resistance and higher dilatation than fine geofoam-sand mixture

Geofoam , internal friction angle, shear resistance , direct shear test