Consolidated Undrained Characteristics of Low Organic Soil Treated with Crustacean Biopolymer

The low organic soils present in the Kari lands of the Kuttanad region bear significant importance in the design of shallow foundations due to their inherently poor engineering characteristics and usually require stabilization. In recent years, sustainable stabilization practices that rely on waste-derived products are gaining attention. The augmentation of the shear parameters of soils with low organic content by the inclusion of sustainable crustacean biopolymers is a novel method owing to their contribution to waste management. The current study aims to understand the consolidated undrained behavior of chitosan-treated low-organic soils relying on triaxial tests. The tests are performed on samples mixed with 1% and 2% of the biopolymers. The effect of the curing period and confining pressure on these samples are evaluated by conducting consolidated undrained triaxial tests at confining pressures of 50, 100, and 150 kPa to evaluate the efficiency of treatment. The microstructural improvement is confirmed by conducting a scanning electron microscope. The chitosan treatment exhibits a considerable enhancement in effective cohesion by a factor of 1.88 for 60-day cured 2% amended samples owing to the networking of soil particles by fiber formations, as revealed from SEM images. The presence of the fibers contributes to the increase in the angle of internal friction with the curing period. Considering the range of effective cohesion (96.2-142.9 kPa) and effective angle of internal friction (9.4°-20.5°) attained for chitosan-stabilized soil samples, these materials can serve as excellent foundation materials.