Geosynthetic-reinforced soil slopes with different backfills and reinforcements subjected to rainfall infiltration
Journal
11th International Conference on Geosynthetics 2018, ICG 2018
Journal Volume
4
Pages
3339-3353
Date Issued
2018
Author(s)
Abstract
This paper presents a numerical study to investigate hydraulic response and stability of geosynthetic-reinforced soil slopes (RSS) with different backfills and reinforcements subjected to rainfall infiltration. Three backfill materials (i.e. sand, silt, and silty clay), two geosynthetic reinforcements (i.e. geogrid or nonwoven geotextile), and two rainfall intensity (q = 350 and 500 mm/day) are evaluated. The backfills are modeled using three soil–water characteristic curves (SWCCs), representing the general suction range associated with sand, silt, and clay. The numerical results reveal that the initial suction has a significant contribution in enhancing slope stability of reinforced clay slopes at the beginning of infiltration; however, the stability of the reinforced clay slope considerably decreases due to the loss of matric suction and development of a capillary barrier effect at clay-geotextile interface as the rainfall infiltration proceeded. In contrast, the stability of the reinforced sand slope are minimally influenced by the change of soil moisture conditions. The numerical results also indicate that the reinforced marginal soil slopes cannot effectively drain the infiltrating water under given rainfall intensities. Free drainage conditions may not be assumed for these slopes if the drainage is not properly considered. The required reinforcement tensile strengths for the reinforced silt and clay slopes to maintain FS = 1.3 are approximately 3 and 4 times, respectively, larger than that for reinforced sand slopes. Finally, the relationships between the rainfall intensity (I) and rainfall duration (D) are established to determine critical rainfall thresholds when the failure of reinforced slopes occurs. The equation for critical rainfall thresholds (referred to I-D curve) of reinforced slopes with different backfills are proposed and compared. ? 2018 11th International Conference on Geosynthetics 2018, ICG 2018. All rights reserved.
Subjects
Geotextiles; Infiltration; Rain; Sand; Silt; Slope stability; Soil moisture; Tensile strength; Capillary barrier effect; Critical rainfall thresholds; Geosynthetic reinforced soils; Geosynthetic reinforcement; Moisture conditions; Nonwoven geotextiles; Rainfall infiltration; Water characteristics; Reinforcement
Type
conference paper