This paper presents a numerical investigation of water infiltration into a fine-grained reinforced soil wall using nonwoven geotextiles. A large-scale reinforced soil wall was constructed in the laboratory and subjected to water irrigation to impose a controlled infiltration. The structure was fully instrumented to measure changes in the volumetric water content and matric suction during irrigation. The numerical investigation was performed to provide insight into the overall infiltration process, with a particular focus on the hydraulic behavior at soil-geosynthetic interfaces that was not properly captured in the laboratory model. The numerical study includes capillary effects, the location of breakthrough along the reinforcement length and the effect of the presence of a wrap-around anchorage. In general, the numerical analyses were found to agree with the experimental results. The results indicate that the use of nonwoven geotextiles to reinforce fine-grained backfill retarded water flow into the subsequent layers so that the water did not break through uniformly along the length of the geotextile but rather infiltrated progressively. The study also demonstrated the significant contribution of the presence of a wraparound anchorage on the change in the water flow path toward the wall facing. The capillary effects on fine-grained backfill reinforced with geotextiles were found to be significantly affected by the heterogeneity in the porosity expected for compacted soils.
This paper presents a numerical method for considering soil-atmosphere interaction applied to infiltration into an unsaturated geosynthetic reinforced soil wall and its effect on wall stability. A hypothetical nonwoven geotextile reinforced soil wall was subjected to simulated conditions of evaporation and precipitation over 2 years considering local climate variation in São Paulo city, Brazil. Net infiltration and actual evaporation were quantified inside and outside the reinforced zone, allowing for the assessment of changes in soil suction and factors of safety. The study discusses the implications of using in-plane draining reinforcements (e.g. nonwoven geotextiles) and soil-atmosphere effects. Results show that soil suction and factors of safety variation are more dependent on consecutive days of precipitation than on isolated heavy rainfalls. For the climate conditions considered in this study, results show that approximately 50% of the precipitation and potential evaporation transformed into net infiltration and actual evaporation, respectively. Additionally, the numerical results indicate that after the first wetting of the soil inside the reinforced soil zone, the evaporation to the atmosphere did not remove water from the inside of the geosynthetic reinforced wall because of the capillary break.