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

Abstract

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. This study underscores the pivotal role of hybrid geosynthetics in contemporary geotechnical engineering, providing robust solutions for mitigating rainfall-induced challenges in various geotechnical structures. The combination of nonwoven geotextile and geogrid layers in hybrid geosynthetics significantly augments drainage efficiency, particularly in low-permeable soils, attenuating pore water pressures and enhancing its stability. The bottom-up construction methodology for GRSWs facilitates the seamless incorporation of such permeable hybrid geosynthetics alongside a granular drainage layer behind the facing, improving in-plane and vertical drainage and preventing catastrophic failures. This methodology extends the longevity and reduces maintenance expenditures of retaining structures, presenting a durable and economical solution. The research advocates for the development of climate-resilient infrastructure, which is crucial amidst the increasingly erratic nature of rainfall due to climate change. This innovative approach promotes sustainable construction by utilizing locally available fine-grained soils, eliminating the necessity for costly granular materials. Additionally, the findings from the study can help in policy revisions and updating construction guidelines toward safer and more efficient field practices.