Soil hydraulic conductivity control via biopolymer treatment induced bio-clogging effect

Abstract

For deep underground constructions with groundwater, quick and effective in-situ hydraulic conductivity control is important to dissipate the mega hydraulic pressure which becomes critical to underground structures after construction. Recent permeability control methods (e.g., grouting, membranes, pumping, and drain) have several drawbacks, such as setting time, washout, or installation difficulties. Gellan gum is a microbial induced biopolymer with the capabilities of forming hydrocolloid gels when mixed with heated water and limiting water flow through the gel itself. The focus of this study is to investigate the possible usage of gellan gum biopolymer in soil hydraulic conductivity control at various depths and pore pressure conditions. Hydraulic conductivity of gellan gum treated sands were used for laboratory testing.Various pore water pressure and confinement conditions were simulated via pressurized syringe pump permeability testing device to observer the bio-clogging behavior of gellan gum treated sands under high pressures. In addition, soil hydraulic conductivity variations due to overburden confinement and pore water pressure changes were observed. With its quick setting time and soil enhancing properties, the use of gellan gum biopolymer for soil hydraulic conductivity control shows promising results to become an environmentally-friendly alternative in in-situ grouting purposes.