Effect of gravel size and geogrid opening variation on the reinforced of the unpaved roads

Abstract

In unpaved roads, the bare soil of the soft subgrade or the covered grading layer of subgrade soil has traditionally been the focus of embankment and pavement loads. Using geogrid as isolation and reinforcement between road layers is a widely accepted method to solve this problem. This study used the California Bearing Ratio (CBR) test to evaluate the geogrid reinforcing effects among geogrids with various aggregate particle sizes and the size of the openings of the geogrid. The research results show that when the particle size of the subbase layer was controlled and the ratio of the geogrid opening was variated, the bearing capacity was improved relatively more significantly. The contribution of geogrid to CBR value increased from 12% to 50%. In the reinforced system with a fixed geogrid opening aperture, increasing the particle size of the aggregate will increase the overall bearing capacity of the reinforced system; however, when the size of the aggregate increases to a certain level, the contribution rate of the geogrid CBR value changes relatively indignantly. Additionally, in the reinforced system, by fixing the particle size of the aggregate and adjusting the ratio between the aggregate particle size and the geogrid opening aperture, the overall bearing capacity of the reinforced system is still improved, and the CBR contribution rate provided by the geogrid changes relatively significantly. Finally, the research results also show that the 3Dprinting geogrid had a similar effect to the commercially available geogrid. Therefore, different types of geogrids could be made in follow-up research, and further analysis had the best effect. The particle size of the gravel with the best-reinforced effect and the ratio of the geogrid opening can provide a reference for engineering design.