Dynamic characteristics and reinforcement mechanism of silty soil improved by regenerated fiber polymer

Abstract The development of economical and efficient roadbed silt reinforcement technology not only guides the proficient utilization of silt resources but also fosters the green development of geotechnical engineering construction. Ensuring the robust dynamic stability of the roadbed is pivotal for the safe operation of vehicular traffic. In this context, employing recycled polyester fibers and inorganic curing agents, this paper leverages dynamic triaxial testing and scanning electron microscopy (SEM) methods to scrutinize the dynamic characteristics and microscopic mechanisms of recycled fiber polymer modified roadbed silt. The findings indicate that: (1) with a fiber content of 0.2%, the fiber-modified soil sample exhibits minimal damage, maximal dynamic strength and dynamic elastic modulus, and optimum resilience to dynamic loads; (2) akin to fiber-reinforced sand, an elevation in confining pressure can induce the creation of a quasi-cohesive force in fiber-reinforced soil, equivalently enhancing the confining pressure and thereby amplifying its strength; and (3) the surfaces of microparticles in the enhanced soil structure are enveloped with cementitious substances, while smaller soil particles coalesce to form aggregates that fill inter-particle pores, cultivating a denser and more stable improved soil structure and augmenting the dynamic characteristics of the improvement investment.