Experimental study on influence of geo-cell reinforcement on dynamic properties of rubber-sand mixtures

The rubber-sand mixtures (RSM) are more and more widely used in civil engineering as light filling and energy absorbing materials. The geo-cell can be used to reinforce RSM to improve its shear strength and stability. Little knowledge has been reported on the dynamic properties of RSM or geo-cell reinforced RSM (GCRSM). Based on this, the hysteretic properties of RSM with or without geo-cell reinforcing under cyclic horizontal loadings are investigated through large-size cyclic simple shear tests. The hysteretic curves, dynamic shear modulus curves and damping ratio curves of RSM and GCRSM are obtained by tests and fitted by the Stokeo-Darendeli model to gain parameters of dynamic properties. The comparative analysis of dynamic properties between RSM and GCRSM is carried out, and the rules and mechanisms of how the geo-cell influences the dynamic properties of RSM are verified. The test results show that: (1) Owing to the restriction of local shear band development in the specimen by the geo-cell, the S-shaping characteristics is less pronounced and the damping ratio increases under large strains when comparing GCRSM to RSM. (2) The dynamic shear modulus of RSM is increased by the geo-cell reinforcement, and the increment becomes more pronounced with addition of rubber content of RSM, which is believed due to the normal stress increment between particles in RSM caused by tuck net effect of geo-cell. (3) The influence of cycle numbers on dynamic properties of RSM decreases with use of geo-cell reinforcement. The decay velocity of the maximum dynamic shear modulus of RSM with both rubber content and vertical pressure is reduced when the geo-cell is used to reinforce RSM. Quantitative influences of geo-cell reinforcement on the dynamic characteristics of RSM are also provided for reference of the following researches and engineering applications.