Papers abstract:

A Finite Element procedure was used to investigate the reinforcement load and the deformation mode for geosynthetic-reinforced soil (GRS) walls subject to seismic loading during their service life, focusing on those with marginal backfill soils. Marginal backfill soils are hereby defined as filled materials containing cohesive fines with plasticity index (PI) >6, which may exhibit substantial creep under constant static loading before subjected to earthquake. It was found that under strong seismic loading reinforced soil walls with marginal backfills exhibited a distinctive “two-wedge” deformation mode. The surface of maximum reinforcement load was the combined effect of the internal potential failure surface and the outer surface that extended into the retained earth. In the range investigated, which is believed to cover general backfill soils and geosynthetic reinforcements, the creep rates of soils and reinforcements had small influence on the reinforcement load and the “two-wedge” deformation mode, but reinforcement stiffness played a critical role on these two responses of GRS walls. It was also found that the “two-wedge” deformation mode could be restricted if sufficiently long reinforcement was used. The study shows that it is rational to investigate the reinforcement load of reinforced soil walls subject to seismic loading without considering the previous long-term creep.

Product Overview:
This tutorial examines the deformation mode of geosynthetic-reinforced soil (GRS) walls (with marginal backfill soils), and the reinforcement load under seismic loading during their service life. Also, it’s identified that how the creep (time-dependent deformation) influences the response, and the role of reinforcement stiffness and length in controlling seismic performance. Key simulation steps include:

• A Finite Element (FE) model was reconstructed to simulate the long-term creep and seismic response of GRS walls, which was validated using results from centrifuge tests conducted at Tsinghua University.
• The model accounted for strain rate effects, cyclic hysteresis, and stress relaxation.
• A “two-wedge failure mechanism” was identified under seismic loading:
  • Internal failure surface (close to Rankine’s failure plane) develops in the reinforced zone.
  • Outer failure surface extends from the base into the retained soil.

In this tutorial, the Reinforcement load and deformation mode of geosynthetic-reinforced soil walls simulation results, was reconstructed according to data from the work of Liu et al.