Slope Stabilization for Local Government Engineers in Minnesota

The purpose of this paper is to describe development of a design guide focusing on stabilization of locally-maintained slopes. Motivation for this project came from engineers experiencing recurring slope failures, especially following heavy rain events or spring thawing. There is currently no guide for public works engineers to stabilize slopes of the scale typically seen along locally maintained roadways in Minnesota. Therefore, slope failures can damage roads, pose safety hazards, and introduce preventable maintenance and repair costs. While there is no single stabilization method appropriate for all situations, several methods have proven effective. Local government engineers requested guidance on stabilization methods available without paying for specialty equipment or hiring a geotechnical consultant. This study addresses the need to provide a consistent, logical approach to slope stabilization founded in geotechnical research and applicable to common slope failures. First, the authors identified slopes for further analysis via a survey sent to each county engineering department in Minnesota and conducted site investigations to characterize sites experiencing recurring failures. Laboratory and in situ testing quantified slope geometry and soil strength properties for each of the slopes requiring maintenance. Additionally, limit equilibrium method models were developed for each slope to investigate different stabilization methods in a parametric study. Finally, modeling and analysis results were summarized in a design guide for distribution to local government engineers. The deliverable will assist with efficient stabilization method selection for common slope failures along roadways.