Confidential Project - Earth Retention in the Rocky Mountains on a Moving Landslide-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes roadway construction for a private recreation development in the Southern Rocky Mountains, an area mapped as having moderate-to-high landslide potential and receiving about 35 feet of snow annually. The project includes six miles of access roads across 200 acres, requiring retaining walls in steep terrain.<br /><br />The site is affected by a pre-existing landslide in weak siltstone, claystone, and sandstone. Its movement was documented from October 2021 through May 2022. Because cutting slopes can reactivate or accelerate landslides, the project required extensive investigation: 65 borings and 48 test pits. Design criteria included long-term slope stability with a factor of safety of 1.5, and seismic performance limited to two inches of deformation.<br /><br />Three wall systems were selected according to slope geometry, instability depth, and support demands. Tecco mesh walls use solid steel bars and mesh facing for steep slopes where movement can mobilize passive support. Soil nail walls use bars and shotcrete facing, typically on vertical or near-vertical cuts. Tie-back walls provide active, prestressed support for deeper instability and higher loads, using long anchors and reinforced shotcrete.<br /><br />The presentation outlines verification and production testing requirements for each system, with test loads ranging from 133% to 200% of design load. It also shows completed examples of all three wall types.<br /><br />The development offers privacy and recreational opportunities, including skiing, hiking, fishing, hunting, biking, and horseback riding. However, high membership costs, unknown annual dues and lot costs, legal delays, and the site’s location on a moving landslide are significant drawbacks.

Keywords

roadway construction

landslide potential

retaining walls

slope stability

soil nail walls

tie-back walls

Tecco mesh walls

snowfall

Rocky Mountains

geotechnical investigation