Effectiveness of jute geotextile filter for river bank protection

Abstract

This study was undertaken to investigate the effectiveness of Jute Geotextile (JGT) as filter material for river bank protection. Two types of JGTs were selected for the study. Some physical, mechanical and hydraulic property tests were performed on the selected JGTs. It is appreciated that neither any standard test method nor any design approach related to JGT is currently available. The ASTM and DIN standard test methods for determining the properties commonly employed for synthetic geotextiles were adopted. To investigate the effectiveness of JGT in river bank protection, both field trial and laboratory simulation were performed. For field trial, a site was selected where river bank protection work was going on. Soil samples were collected from the river bank. Grain Size Analysis was performed on those samples in order to investigate formation of filter cake underneath the JGT. For laboratory simulation, a model was arranged in geotechnical laboratory of BUET. Soil collected from the river bank was used in the model and untreated JGT was used as a filter material. Reversing water flow was conducted through the model setup for a certain time. After that time, water flow was stopped and soil sample was collected from the setup. Grain Size Analysis of the soil sample was performed to examine the redistribution of particle size of the soil. From field trial it was found that, when JGT is used as filter material in river bank protection, natural soil filter cake is formed partially. Since the river bank remained in good shape for more than two years, it can be said that the partially formed filter cake is stable. From laboratory simulation, it was found that filter cake forms partially after a certain period of time. Both the field trial results and laboratory simulation results indicate that the JGT may be considered as an alternative to synthetic geotextiles as filter material for protection of bank slopes of mild to moderate rivers.