Application of colloid-sand coating treated by a hydrophilic polysaccharide biopolymer material for topsoil stability control

Extensive efforts have been made to resist topsoil instability by enhancing the inter-particle cohesion for the loose structure and weak cohesion of natural sand. In this study, considering the ecological and environmental aspects, an eco-friendly composite material, namely, a hydrophilic polysaccharide biopolymer (HPB) binder, was employed for the topsoil stability. A series of laboratory tests and numerical simulations were conducted to explore the properties and cohesion mechanism of modified sand. The results indicated that the HPB could significantly improve the mechanical properties of the natural sand due to the strong inter-particle bond offered by the network membrane structure. The anti-erodibility of the modified sand was improved, and a capacity to resist erosion of the topsoil by the combined effects of surface covering, strong intergranular bonding connections, and tiny pore throats was observed. This binder provided an appropriate environment for vegetation growth and significantly decreased the erosion rates after vegetation was established. The modified slopes maintained long-term stability by the integrated system of the sand- biopolymer matrix and plant matter. This research can help in the analysis and application of modified technology to control topsoil failure..