PERILAKU INTERAKSI TANAH-GEOTEKSTIL TERHADAP PARAMETER KUAT GESER

Abstract

Soil reinforcement using geo-textile is one of geotechnical structures, involving soil-structure interaction. Recently, the problems are solved by neglecting the interface influence between soil and structure. To obtain more realistic stressstrain relationship, it is required to study the soil-structure interface. The study of behavior of soil-geotextile interaction on the shear strength parameters is discussed in this research. The used soils in this research are uniform sand and clay. The uniform sand has relative density of 50% and 90%. The clay sample is based on the maximum dry density (MDD) value obtained from standard Proctor test. Determination of interface parameter on the shear strength of sandgeotextile and clay-geotextile is obtained from direct shear test. The interface shear strength parameters are friction angle of interface () and adhesion (ca). The used geotextile types are woven, non-woven and geomembrane. Numerical simulation is also carried out to study the influence of variation values on interface shear strength parameters. Result of the research gives review on the behavior and interface modeling of soil-geotextile. Values of friction angle of interface () obtained from sand-non-woven geotextile are higher than sand- woven geotextile. The value of  obtained from sandgeomembrane is the lowest. Ratio of / for non-woven geotextile ranges between 0.8  1.0. Ratio of / for woven geotextile is about 0.7  0.8. Geomembrane ratio of / is about 0.6  0.7. The value of / is relativelyconstant for sand under both saturated and dried conditions. For clay sample, the values of ca and  are lower than value of soil shear strength parameters. The shear stress of geomembrane interface (HDPE) is the lowest under both saturated and unsaturated conditions. The interface shear strength parameters are influenced by the roughness of material and effective opening size of interface material. For clay, the values of ca/c and / are influenced by saturation conditions of soil. Influence of ca and  parameters is represented by value of Rinterface parameter. Higher Rinterface value will decrease the displacement, moment and shear force and increase the safety factor. The result of this research can give contribution on determination of interface shear strength parameters in the analysis of soil reinforcement using geotextile in order to design optimalization.