Evaluation of the Performance of Hybrid Geosynthetic–Reinforced Soil Walls Subjected to Rainfall in a Geotechnical Centrifuge

In the present study, the centrifuge modeling approach was utilized to investigate the efficacy of dual-functional hybrid geosynthetics as reinforcement in alleviating the destabilizing effects of rainfall on geosynthetic-reinforced soil walls (GRSWs) with low-permeable backfill. A series of centrifuge experiments were executed employing a tailored in-flight rainfall simulation mechanism, generating mistlike fine droplets at 40g on a rigid-facing GRSW with a height of 10 m and provided with a low-permeable silty sand backfill. To comprehensively assess the performance, pore water pressures were continuously monitored using pore pressure transducers. Digital image analysis (DIA) was employed to evaluate surface settlements, wall face movements, and strains encountered by geosynthetic layers during rainfall. The centrifuge test results indicated that GRSW without any drainage provisions developed substantial pore water pressures and experienced a catastrophic slip failure within a brief period of rainfall exposure. Providing a granular drainage layer behind the facing in isolation was noticed to be futile with a GRSW failure in 16.85 days, coupling the drainage layer with hybrid geosynthetic reinforcements with high transmissivity characteristics showcased exceptional hydraulic and deformation characteristics and demonstrated remarkable resilience even under the influence of an imposed surcharge load. Consequently, rigorous seepage and stability analyses were performed, yielding outcomes in consonance with the observations from the centrifuge experiments. The integration of hybrid GRSW with the drainage layer behind the facing experienced considerably low pore water pressures and high safety factors, even following exposure to a 30-day antecedent rainfall.