시료입경이 지오그리드로 보강된 조립토의 전단거동 특성에 미치는 영향

Abstract

In this study, large direct shear tests on three types of coarse grained soils (maximum particle sizes of 4.75mm, 7.9mm and 15.9mm, respectively) were performed to understand the effects of particle size on the shear behavior of coarse grained soils with/ without geogrid reinforcements. In the case of coarse grained soil without geogrid, the maximum shear stress increased with an increase in normal stress for medium and large particle sizes. The volume change of the coarse grained soils was similar to that of dense sand, and the expansion of volume became larger with increasing normal stress. The larger the particle size, the smaller the internal friction angle. The internal fricton angle was in the range of 64% to 95% of the internal friction angle of the coarse grained soil without geogrid. Considering the fact that all the conditions were the same for different particle sizes, the difference in the shear behavior of coarse grained soils with geogrid reinforcement results from the discrepancy in the particle size. The cohesion of the soil reinforced with stiff geogrid is 37∼50% larger than that of the soil reinforced with soft gegrid. This difference is because the case with stiff geogrid has more soil to geogrid contact area, leading to the reduction in interlocking between soil particles.