LANDSLIDE REPAIR ON TOP OF A BLUFF: RIVERVIEW DR.-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes repair of a landslide beneath Riverview Drive in Alton, Illinois. Following heavy rains in spring 2019, cracks appeared in July and worsened over subsequent weeks. The road was closed on August 13, and soil investigations using SPT and CPT were conducted on August 19. Despite an initial repair proposal estimated at $350,000 and 15 days, the slope failed on January 19, 2020.<br /><br />After the failure, a revised proposal estimated costs of $3.8–$4.6 million and 130 days. The city pursued FEMA funding and issued a request for qualifications in March 2022. GSI was selected with a $4.3 million bid and a 96-day schedule; the city’s share of the cost was estimated at $1.25 million. Drone surveys helped document the slide’s geometry.<br /><br />The final design had three main goals: stabilize the slide, rebuild the grade and support the road, and protect the slope. Proposed measures included a soil nail wall and slope unloading; a geosynthetic confined soil (GCS, also known as GRS) wall supported by a micropile structural slab; and drainage, a drain line down the slope, and pin-and-mesh surface reinforcement. Construction also involved potholing to locate a waterline and installing rockfall mesh.<br /><br />The case illustrates the progression from early cracking and monitoring to a major slope failure, followed by a more extensive stabilization and roadway-support project.

Keywords

landslide

Riverview Drive

Alton Illinois

slope stabilization

soil nail wall

micropile

geosynthetic confined soil

drainage

FEMA funding

roadway repair