Large-scale field test on deformation mechanism and stability enhancement of soil slope reinforced by the micro-NPR bolt

Bolts play a critical role in landslide disaster prevention and control as an effective slope reinforcement method. Generally, the Poisson's ratio bolt (PR bolt) has a limited effect in controlling large slope deformations, and the negative Poisson's ratio bolt (NPR bolt) has a high constant resistance and adapts to large deformations, which can partially solve the problem of large slope deformations. Static tensile tests were conducted to compare the mechanical properties of PR and NPR bolts. A large-scale field test was conducted to study the differences between the effects of PR and NPR bolts on the soil slope reinforcement. Terrestrial laser scanning was used to monitor the slope damage process and establish a high-precision digital displacement model to reveal the slope deformation evolution law and failure mechanism. In addition, the bolt reinforcement mechanism was analyzed based on data such as soil pressure and axial force. The NPR bolt effectively blocked the transmission of the slope top load, strengthened the internal stress regulation ability of the slope, and prolonged the damage time of the slope. The results provide notable information on the mechanism, macro-mechanical properties, and field engineering applications of NPR bolts.