Best Project, Small Project Riverview Drive Retaining Wall Stabilization
The $4.2-million project repaired and stabilized a roadway in Alton, Ill., situated on top of a 150-ft bluff with views of the Mississippi River. The road started showing signs of movement in July 2019, leading to its closure. The slope failed in January 2020, removing about 15 ft of the roadway and creating a deep scarp about 23 ft deep. Below the scarp, the slope of the bluff is about 55 ft long at a 53-degree angle below horizontal and it terminates at a 60-ft-tall vertical limestone face.
To repair the slope and restore the road, the team installed a soil nail wall; a geo-synthetically confined soil retaining wall; and a soil nail and mesh surface stabilization system. The soil nail wall was constructed near the center line of the road to provide lateral stability. A long reach excavator was used to install the wall, preventing the need for excessive excavation to achieve access to the front of the wall.