Experimental and numerical study on compacted sand bentonite-tire fiber composite for landfill application

Abstract

The primary aim of the present study is to investigate effect of tire fiber on the shrinkage, hydraulic conductivity and shear strength of sand-bentonite (SB) mixture. The secondary aim is stability analysis of the liner slope with the help of modified fiber soil composite instead of orthodox liner material. A series of consolidated undrained triaxial (CU) and oedometer tests were conducted on sand-bentonite mixture mixed in a proportion of 90:10 and added with tire fibers in a proportion of 0, 5, and 10%. Results indicated that by increasing the tire fiber content the hydraulic conductivity of the mixture increases. From the shrinkage study, volumetric shrinkage (VS) was reduced as the tire fiber content increased. Surface crack and shrinkage crack developed in the mixture after desiccation and expressed in terms of crack intensity factor (CIF) as well as crack density factor (CDF) and both reduced with the addition of tire fiber. Triaxial test results suggested that shear strength parameter and initial tangent modulus enhanced with the percentage of tire fiber increased. Negative excess pore water pressure decreased with increase in tire fiber content. MSW landfill liner model was developed and numerical study had been conducted to investigate the stability as well as the total displacement of landfill liner slope. The analysis suggested that factor of safety increased and total displacement reduced due to the reinforcement effect on liner material (i.e., SB tire fiber composite).