Soil-structure interaction of Mechanically Stabilized Earth (MSE) retaining walls subjected to construction sequencing and seismic loading

Abstract

Mechanically stabilized earth (MSE) wall systems are a retaining wall system consisting of facing elements, soil reinforcement, and backfill material. To accurately model this soil-structure, soil structure elements or interface layers are critical to modelling since the load transfer from geosynthetics to backfill material is affected by backfill properties, geogrid length, geogrid spacing, and material properties of reinforcement. Utilizing 3D finite element software, simulation of general construction sequencing and seismic loads is conducted to determine the complex nature of 5 m and 10 m MSE walls. A parametric study was completed, varying backfill and geogrid spacing. This study indicated that limiting fine content of backfill was 24.60%, 47.61%, 53.83% for 5 m wall height while 12.78%, 14.50%, and 34.33% for 10 m wall height, when relating fine content to maximum lateral displacement. The dynamic characteristics, i.e. approximate natural frequency range through frequency sweep, was approximated to be about 4.00 Hz to 4.60 Hz for 5 m MSE wall (for peak response in velocity and acceleration, respectively). For 10 the m wall a peak response for both velocity and acceleration was obtained at 3.0 Hz. Because of the clayey soil characteristic of the unreinforced area, it is recommended that ground improvement techniques be applied before construction of MSE walls.