Effect of temperature on geogrid-facing connection force and lateral earth pressure based on innovative testing method

Conventional geosynthetic-reinforced soil (GRS) retaining wall design guidelines focus on the horizontal reinforcement tensile force calculated based on lateral earth pressure under constant backfill temperature, while giving insufficient attention to the actual connection mechanism between the wall facing and the reinforcement. This limitation may impact the service life of retaining walls. In this study, a novel testing method was developed to simulate the differential settlement between the backfill and the facing within walls, enabling a new approach to quantify the reinforcement-facing connection force under various temperature conditions. Test results demonstrated that this connection force significantly exceeds the measured horizontal reinforcement tensile force under high vertical stress, and the ratio tends to increase with rising temperature under the same vertical stress. Additionally, the lateral earth pressure exerted on the wall back increases with the reinforcement stiffness, but it remains lower than the Rankine active earth pressure. At low temperatures, the conventional estimation method based on Rankine theory was shown to significantly underestimate the actual connection force. The study provides insights for the modification of the current GRS wall design guidelines.