Experimental study on dynamic elastic modulus and damping ratio of lignin-fiber-reinforced sandy soil

Lignin fiber is a type of green reinforcing material that can effectively enhance the physical and mechanical properties of sandy soil when mixed into it. In this study, the changes in the dynamic elastic modulus and damping ratio of lignin-fiber-reinforced sandy soil were investigated through vibratory triaxial tests at different lignin fiber content ( FC ), perimeter pressures and consolidation ratios. The research results showed that FC has a stronger effect on the dynamic elastic modulus and damping ratio at the same cyclic dynamic stress ratio ( CSR ); with the increase in FC , the dynamic elastic modulus and damping ratio increase and then decrease, showing a pattern of change of the law. Moreover, perimeter pressure has a positive effect on the dynamic elastic modulus, which can be increased by 81.22–130.60 %, while the effect on the damping ratio is slight. The increase in consolidation ratio increases the dynamic elastic modulus by 10.89–30.86 % and the damping ratio by 38.24–100.44 %. Based on the Shen Zhujiang dynamic model, a modified model considering the effect of lignin fiber content FC was established, and the modified model was experimentally verified to have a broader application scope with a maximum error of 5.36 %. This study provides a theoretical basis for the dynamic analysis and engineering applications of lignin-fiber-reinforced sandy soil. • New materials for sand reinforcement are proposed. • Fiber incorporation can effectively improve the dynamic elastic modulus and damping ratio of sandy soil. • Modified dynamic constitutive model considering the effect of fiber doping. • The modified dynamical eigenmodel predicts the experimental data more accurately.