Experimental investigation of influence of clay in soil on interface friction between geotextile and clayey soil

Abstract

Although the soils are not always pure in nature and are found as a mixture of clay, silt, sand, or coarse soil grains, pure clay or sand soils are used in all studies related to this subject in the literature. In this study, the influence of clay inclusion in sand on the mechanical behavior of nonwoven geotextile interfaces over clayey and soil and interfacial stress is studied. A relatively well-graded angular sand and a clear smectite type clay were selected as granular material. In all clay-sand mixing percentages, shear box experiments were performed in both dry and water-saturated. When the clay ratio is high, the maximum interfacial stress is around 15 kPa, whereas in the case of the sand ratio is highest, the interfacial stress varies between 30 and 35 kPa. However, as sand grains increase, the failure mechanism becomes more brittle. Geotextile-reinforced samples were investigated while varying the amount of clay in sand layers of saturated and dry condition. Variation of the amount of clay in the sand at the shear box tests showed that the mobilized friction angle between mixed soil and geotextile has a key factor in evaluation of failure in shear strength of mixed soil.