Soil nailing for rehabilitation of reinforced earth wall distress

Abstract

In the present study, an investigation was performed to assess the possible cause of distress to the geogrid reinforced earth walls constructed for a flyover. The investigation methodology included site visits and observations, collection of the material samples (backfill and geogrid) for laboratory testing, and back analyses of original design using a conventional method and numerical analysis. The temporary rise of pore water pressure due to the heavy rains during the construction period and the internal stability of reinforced earth walls have been identified as the possible causes of the observed distresses. Further, installation of the driven soil nails of specified diameter and length at suitable spacings, particularly in the locations of distress, were proposed as the rehabilitation measure. The results of the numerical analyses indicated that introduction of soil nails: (a) caused redistribution of axial forces among the geogrid layers and soils, (b) significantly reduced the lateral displacement and (c) improved the overall stability of the reinforced earth walls.