A General Review of Mitigation Measures for Slope Stability Problems in AK

Abstract and project information last updated: 1 March 2011. Project updates are dated below.

AUTC
Project
Number
309032R
Principal
Investigator
Margaret Darrow (UAF)
margaret.darrow@alaska.edu
Funding
Agency

US Department of Transportation (RITA)

UAF College of Engineering & Mines

Project
Budget
195300
Start
Date
1 October 2010
Estimated
End Date
31 December 2011

Abstract

The failure mechanisms of unstable soil slopes in permafrost areas are not well understood. Analysis of these slopes requires consideration of soil temperatures, ice content, and their effects on soil strength, which is not part of typical slope stability analysis. These unstable slopes may vary in depth, affecting only the active layer or having a more deep-seated nature. Additionally, the subsurface conditions may be a complex mixture of frozen and unfrozen areas, which affects the groundwater flow and overall slope stability. Whatever their configuration, these unstable slopes possess characteristics that are unique to permafrost regions.

Several unstable soil slopes in frozen ground exist along highways in Alaska’s Northern Region. These areas of instability require ongoing maintenance and monitoring until possible mitigation strategies are developed. Without understanding the intricacies of these unstable slopes in frozen ground, the engineers from the Alaska Department of Transportation and Public Facilities (AK DOT&PF) may be at a disadvantage when developing mitigation strategies.

The research objectives of this project are: 1) to provide a comprehensive review of literature on unstable soil slopes in permafrost areas, including an overview of both successful and unsuccessful mitigation strategies that were applied previously; 2) to summarize case studies of key historic and/or ongoing unstable soil slopes in AK DOT&PF’s Northern Region; and 3) to develop a training product for AK DOT&PF engineers that categorizes typical unstable soil slopes in permafrost areas within AK DOT&PF’s Northern Region, and appropriate mitigation strategies. This training product will provide background and guidance to engineers at AK DOT&PF who will need to develop mitigation strategies for similar slopes in the future.