In the Spring of 2016, JC Hines & Associates partnered with Schreiter Concrete to develop plans for a Redi-Rock retaining wall at a QuikTrip gas station in St. Peters, MO. The wall would be located along the intersection of McClay Road and Jungermann Road, and line the border of the QuikTrip and its neighboring property.

Tight spatial limitations meant the wall would need to be designed without geogrid reinforcement. At 15 feet tall, the gravity wall supports the parking area on the adjacent property and was designed for potential traffic impact loads on a wall-mounted railing system. To add more complexity to the design process, the geotechnical reports revealed the wall would be founded in clay soil with marginal shear strength.

After the design parameters were clearly defined, the design team at JC Hines & Associates could prepare an optimized solution – A “Geotextile Burrito.”

The foundation improvements involved an undercut and No.2 rock fill, wrapped in a woven stabilization geotextile. Four feet beneath the leveling pad and ten feet wide, the undercut zone was reinforced with three layers of biaxial geogrid spaced vertically at 12-inches with the No.2 rock fill between layers, and a woven stabilization geotextile wrapping the entire undercut zone – like a burrito. This soil mitigation technique transformed the soils immediately below the base course of the wall into a geosynthetic reinforced mass that functions as integral structural footing.

The tallest section of the wall was designed with 60-inch block units at the bottom, transitioning to 41-inch block units in the middle of the wall, and topped with freestanding hollow-core units. The hollow-core was relatively new to the Redi-Rock product line in 2016. With texture on both sides, these blocks look best above grade and make it easy to include rail or fence systems within the design.

The total face area of the Redi-Rock retaining wall is 4,975 square feet. All Redi-Rock blocks were manufactured by Schreiter Concrete in Wright City, MO. Construction was completed in 2017.