Dynamic properties of EPS beads lightweight soil mixed with polypropylene fiber

EPS beads lightweight soil composite is a new type of artificial geotechnical material, with low density and high strength characteristics, which can be widely used and plays an important role in engineering projects. To study the dynamic properties of EPS beads lightweight soil mixed with polypropylene fiber (FELS) under cyclic loading, dynamic triaxial test was conducted on EPS beads lightweight soil mixed with polypropylene fiber (FELS) with different EPS contents, cement contents, and confining pressures. The results showed that under the same dynamic stress, the dynamic strain increased with the increase of EPS content and decreased with the increase of cement content and confining pressure. The dynamic shear modulus decreased with the increase of EPS content and increased with the increase of cement content and confining pressure. The inverse of the dynamic shear modulus showed an excellent linear relationship with the dynamic strain. The attenuation model of the dynamic shear modulus ratio of FELS was established. The more the EPS content was, the greater the damping ratio was. The damping ratios of the samples with different EPS contents increased slowly and close to one another in the early stage of dynamic stress loading. However, they rapidly increased in the late stage, and the gaps among them were noticeable. The damping ratio was negatively correlated with the cement content and the confining pressure. Combined with the macroscopic mechanical properties, the microscopic SEM observation was carried out to analyze the microscopic mechanism of FELS.