Geogrid Reinforced Soil Walls with Marginal Backfills Subjected to Rainfall: Numerical Study

Abstract

Altering natural landforms without impacting stability has become quintessential due to unprecedented infrastructure development. Geosynthetic reinforced soil wall (GRSW) as a retaining structure is a congenial option addressing land scarcity and right of way challenges. However, with dearth of good-quality backfill soil and prohibitive transportation costs, engineers are being forced to use native low-permeable marginal soils for constructing geosynthetic reinforced soil walls. Adverse climatic changes leading to erratic rainfall have triggered numerous failures in such soils due to their inefficiency to dissipate excess pore water pressure. The objective of the present paper is to evaluate applicability of different backfill soils for GRSW. Seepage and stability analyses were conducted to appraise the behaviour of a geogrid reinforced soil wall with rigid facing of height 9.6 m having 6° batter during rainfall. The effects of backfill soil types with fines content of 0%, 20% and 40% on seepage behaviour and stability were assimilated under moderate rainfall. It was ascertained that failure occurred faster when the backfill soil with 20% fines was considered. For backfill soil with 40% fines, a significant portion of rainfall was observed to simply disappear as runoff. In the section with sand backfill, failure did not occur as water drained off faster than rainfall infiltration, restraining mounting of water table.