Standard practice for the compaction of the backfill soil near the facing of an MSE wall or embankment is to use lightweight compaction equipment to prevent excessive facing deformation. Complications due to compaction using heavy equipment near the facing could also include misalignment or structural damage of the wall facing and overstressing of the reinforcement layers. However, inadequate compaction near the facing could result in later settlement or appearance of voids behind the facing. Little research has been reported in the literature to quantify the effects of loosely compacted soil behind the facing on the stability and serviceability of MSE walls at the end of construction. In this study, the influence of inadequate compaction effort near the facing on the construction performance of idealized wrapped-face MSE wall models is investigated using a numerical simulation approach. It is shown that inadequate backfill compaction within 1 m of the wall facing could increase the wall lateral displacement by about 40% and the reinforcement strains by about 90% compared to the response of an otherwise identical (i.e. control) wall model constructed with uniform compaction throughout the backfill. This effect was found to be more significant for higher quality backfills with greater friction angle values and less stiff reinforcement materials. Results of this study on idealized wrapped-face wall models highlight the importance of proper soil compaction and quality control near the facing of MSE walls and offer example quantitative increases that could be expected in the out-of-alignment and reinforcement loads in these MSE structures.
Abstract