Study on Mechanical Performance and Reinforcement Mechanisms of Geocell-Reinforced Soil

A concept for a reinforcement mechanism is presented and analyzed combined with test results to explain the reinforcement effect of a geocell. A series of pull-out and unconfined compression tests were carried out to investigate the effect of various parameters, including water content, compactness, and the number of geocell-reinforced layers, on the mechanical performance of geocell-reinforced soil. The results of the pull-out tests were mutually verified by the formulas for the reinforcement mechanism and demonstrate that the compactness and water content significantly affect the friction coefficient of the geocell–soil interface, which increases as compactness rises and water content falls. Compared with lowering the water content, improving compactness was better for enhancing the frictional properties of the geocell–soil interface; this had the highest increase, at 90%, as compactness rises from 92% to 94%. According to the unconfined compression test results, the unconfined compressive strength of geocell-reinforced soil is raised by higher compactness, more geocell-reinforced layers, and lower water content; this had the highest increase, at 93.1%, as the water content dropped to its optimum, from 19% to 15%. The compactness of filled soil dramatically influences the unconfined compressive strength of unreinforced specimens, which had an increase of 59.6% when compactness rose from 92% to 94%. However, this effect was weakened as more geocell was added to filled soil. As the number of geocell-reinforced layers rose from 0 to 1 under the compactness level of 92%, the increase of ultimate unconfined compressive strength reached 82.6%, higher than in other reinforcement layers.