Permanent Soil Nail Wall Utilizing Chemical Grout Stabilization

A permanent soil nail wall was constructed to support an existing bridge abutment of an active major interstate. During the construction of the wall, poorly graded sand with trace silt (SP) was encountered directly beneath the abutment footing. The soil did not posses sufficient "face stability" to permit soil nail wall construction to proceed as originally designed. Further investigations determined this soil condition to be present the full depth of the proposed excavation support system thus requiring an alternate solution to be implemented. Due to restrictions associated with future roadway construction, sodium silicate based chemical grouting of the excavation face along the full height of support was selected to temporarily stabilize the poorly graded sands and permit the originally designed soil nail wall to be constructed. This paper discusses the conceptual design and construction procedures utilized to carry out the grouting program and soil nail wall construction.