Alabama Department of Transportation (ALDOT) publicly bid a design-build Request for Proposal (RFP) to solicit competitive proposals (Technical Proposals and Bid Price Proposals) from qualified Design-Build-Warranty firms for work activities required to design and construct slope stabilization systems for I-22 West Bound at MM 17.400. This location is an existing 3:1 cut slope that has been re-shaped several times and remained unstable with vertical scarping present in multiple locations. The instability was due to, among other things, the existing slope configuration, soil conditions, ground water seepage, and rainfall saturation. The surface sloughing and deeper failure created heave at the toe of the slope adjacent to the road.
The project was awarded to the GeoStabilization Design-Build-Warranty team. The repair system included a two-tiered soil nail wall measuring a distance of approximately 950 linear feet with individual wall heights up to 40 feet (over 23,000 SF of soil nail & shotcrete walls). This work included massive excavation and permanent soil nails capable of producing a global factor of safety greater than 1.3. Due to the emergency nature of the project, GeoStabilization was tasked with expediting the completion of the project while working through Northern Alabama’s winter months that were plagued with heavy precipitation. GeoStabilization deployed multiple crews to the site complete with project managers and project engineers to complete the project ahead of schedule.
A variation of karst sinkhole grouting is the grouting of mined coal seams and workings located below existing infrastructure that exhibit the potential to propagate to the surface and cause sinkholes and/or subsidence.