Laboratory assessment of soil-Jute geotextile interaction behaviour

Abstract

This study was undertaken to assess the interaction behaviour of soil jute geotextile. The thesis presents the results of an investigation into soil - jute geotextile interaction by means of pullout tests. For this purpose a large size pullout box was designed and constructed. Pullout test results can be severely affected by boundary conditions, in particular by the lateral earth pressure developed on the front wall of the box, short lengths of jute geotexti Ie, depth to length of reinforcement ratio, relation between soil particle size and container volume, side friction developed on the wall and soil dilatancy. In order to avoid this effect, sleeves at the front wall and fiber glass sheets were used in the front and side walls of the pullout box. Two types of untreated jute geotextiles samples were obtained from BJMC and BJRI. Mechanical and Hydraulic properties of these jute geotextiles were determined following the ASTM standard test methods. Dredged fill sand samples used for the pullout test were collected from the stack yard of Kaliakoir By Pass Construction Project, Joydevpur-Tangail Road, Gazipur, Bangladesh. The Index and shear strength properties of sand samples were determined following ASTM standard test methods. Soil reinforcement interaction is a primary issue for designing'of any reinforced soil structures. The soil to jute geotextile interaction parameters are influenced by interaction mechanism between sand samples and jute geotextiles, physical and mechanical properties of sand samples (density. grain size distribution, shear strength of sand samples) and mechanical properties (tensile peak strength), shape and geometry of jute geotextiles. The soil to jute geotextiles interface friction parameters (interface friction angle "8" and coefficient of interaction "C;"") for different surcharge pressures were investigated. For this purpose, a number of pullout tests were carried out to evaluate the intcrface friction parameters of two types of jute geotextiles (Wool Pack and DW Jute Bag) and sand samples. The results of this study indicate that the dredged fill sand soils can be successfully reinforced with jute geotextile rcinforcements and the coefficients of interaction (0) are equal to 0.9 - 0.95 for all tests indicating good bonding between the tested soil and jute geotextiles. Additionally an assessment of technical and economical feasibility of jute geotextile reinforced steep sloped embankment is also presented in this study. It has been highlighted that despite the extra cost involvement for jute geotextiles used as reinforcements, the net benefit that can be accrued from the other components, e.g. cost of sand, cost of clay, cost of saved lands, revenue earned from the saved lands etc., can be very significant for different heights of embankments .