Hydraulic conductivity behavior of Gellan gum – treated sands considering stress variations in laboratory scale

Biopolymer-based soil treatment (BPST) has recently been introduced as a new ground improvement method for environmentally friendly and sustainable development. Numbers of research have investigated BPST effects on the soil hydraulic conductivity, while there are lack of studies considering in-situ stress (i.e. vertical confinement and groundwater pressure) conditions. In this study, the effect of gellan gum BPST on the hydraulic conductivity behavior of sands was assessed using a pressurized permeability test apparatus which allows separate vertical confinement and pore pressure control. The hydraulic conductivity of gellan gum biopolymer-treated sands were measured with different biopolymer contents, vertical confinement levels, and pore water pressure conditions. Laboratory test results show that the hydraulic conductivity of gellan gum-treated sands attribute to 1) biopolymer-particle bonding, 2) biopolymer hydrogel induced pore-clogging, and 3) hydrogel alteration due to pore pressure increase, where gellan gum BPST is postulated to be an effective manner for ground hydraulic conductivity control in geotechnical engineering practice.