Injection Characteristics of Thermo-Gelation Biopolymers and Impermeability Enhancement in Treated Soils

Abstract

This study investigates the injection characteristics of thermo-gelation biopolymer (TGBP) and its effect on the impermeability of treated soils. Experimental results demonstrate that TGBP exhibits shear-thinning behavior, enhancing its injectability under varying pressures and ground conditions. At a water injection pressure of 100 kPa, TGBP reduced hydraulic conductivity by 100-10,000 times compared with untreated soils. This significant reduction is attributed to TGBP's temperature-dependent sol-gel transition, which effectively fills and hardens soil pores, as observed through microscopic images. Additionally, TGBP achieved 6.3 times greater hydraulic conductivity reduction compared with cement-based grout. The analysis established relationships among injectability, hydraulic conductivity, injection volume, and penetration distance of TGBP. TGBP's environmentally friendly properties, such as reduced carbon emissions, make it a sustainable and effective alternative for geotechnical applications requiring enhanced impermeability. The findings and proposed high-temperature injection method provide valuable insights for future field applications. © 2025 Elsevier B.V., All rights reserved.