Improving erosion resistance of sandy soils using zein biopolymer

Continuous internal erosion, commonly manifested as piping, is a major cause of failure in earthen structures. This study employs the hole erosion test to examine the internal erosion resistance of zein biopolymer–treated soil, encompassing three sandy soil types with varying particle sizes. The gelation mechanism of the zein binder is evaluated through rheological and shear wave analyses. Treated and untreated specimens are subjected to hydraulic gradients at constant flow rates. The erosion analysis focuses on changes in axial diameter, particle loss rate, shear stress, and erosion rate. The biopolymer gel demonstrates evolving rheological behaviour, transitioning from shear thickening to shear thinning after a 4-hour curing period. Treated specimens exhibit improved shear stress and erosion rate over time, which vary with particle sizes. Hydraulic shear stress decreases with the curing period, and particle size increases, correlating with erosion rate reduction. Higher consistency index of the biopolymer gel leads to decreased hydraulic shear stress, influenced by gel internal friction. Hydraulic shear stress linearly relates to shear wave velocity of the treated specimen. Zein biopolymer enhances erosion resistance of cohesionless sand through gel internal friction and treated specimen shear stiffness.