Laboratory tests on engineering properties of a new negative-Poisson′s-ratio geobelt

Abstract

Reinforcement of elevated subgrades, embankments, or slopes is a focus of highway construction projects. In this study, a new negative-Poisson's-ratio geobelt (NPRG) is developed to facilitate such reinforcements. Herein, the NPRG design and manufacturing process are described in detail. Additionally, tensile tests, pull-out tests, and numerical simulations to test the negative-Poisson’s-ratio effect and mechanical behavior of the NPRG in soil are reported. The results show that the NPRG shell structures are lifted by the core structure under tension, thereby expanding the NPRG cross-section. Hence, a negative-Poisson's-ratio effect is generated. Further results show that the negative-Poisson's-ratio effect of the NPRG only appears when the axial strain exceeds 1.2% or 1.6% (from the test and numerical simulation, respectively). Moreover, with 300 kPa as the boundary, the NPRG peak pulling force first increases and then decreases with increasing upper pressure. Finally, the negative-Poisson's-ratio effect of the NPRG disturbs the surrounding soil. Simultaneously, the NPRG cross-sectional expansion makes it more closely integrated with the surrounding soil, thereby, improving the reinforcement effect.