Experimental and numerical investigation into surface strength of mine tailings after biopolymer stabilization

Penetration test has been a promising technique for characterizing the surface strength of a crusted surface. This paper presents an experimental and numerical investigation of using a flat-ended penetrometer to evaluate the surface strength of mine tailings (MT) treated with biopolymer solutions of different concentrations. The experimental results show that the infiltration depth of biopolymer solution into dry MT decreases with the increase in biopolymer concentration. Biopolymer stabilization effectively increases the surface strength and cracking resistance of MT, and the increase is greater when the biopolymer concentration is higher. To further explore how biopolymer stabilization increases the surface strength and crack resistance of MT, numerical simulations using discrete element method were carried out to study the penetration tests on MT treated with biopolymer solutions of different concentrations. The simulation results show that the inter-particle tensile and shear strengths both increase with higher biopolymer concentration, indicating that more biopolymer induces larger inter-particle bonding and thus increases the surface strength of MT. The simulation results also confirm the delayed formation of cracks on MT after biopolymer stabilization from a microscale perspective, leading to a better understanding of biopolymer stabilization of MT.