Combining Rock Slope Ranking Methods and Performance Monitoring Techniques for Rockfall Geohazards to Advance Geotechnical Asset Management in Alberta

• Author / Creator

  Wollenberg-Barron, Taylor DG

• Alberta Transportation and Economic Corridors (TEC) are currently working towards the development and implementation of a formalized Geotechnical Asset Management (GAM) program to manage the diverse range of both geotechnical and transportation assets present along Alberta’s roadway infrastructure. This requires the assessment of available tools to effectively collect and manage data for both funding forecasting and evidence-based decision making.
  The Geohazard Risk Management Program (GRMP) is TEC’s current system for the assessment, monitoring, and prioritization for mitigation of geohazard sites identified along the Province’s roadway infrastructure. The objectives of this thesis were to develop a methodological basis for combining the results of initial condition assessment tools, including the GRMP Risk Level Rating, and slope performance monitoring techniques to provide an additional tool for the prioritization of resource allocation for rockfall geohazards. This included this assessment of applicable initial condition assessment tools, quantifying the results of performance monitoring techniques, and correlating these the results across multiple sites in a practical and repeatable way that TEC could implement as part of a formalized GAM program.
  A suite of potential condition assessment tools was selected from the results of a literature review. The intent of the study was to focus on practical assessment tools which could be applied relatively quickly and without the need for specialized equipment, following the methodology of TEC’s current Regional Slope Tours. The condition assessment tools were applied to several rockfall geohazard sites which existed within TEC’s current asset inventory. The sites were selected to cover a wide range of documented hazard levels to test the effectiveness of each condition assessment tool in Alberta’s geological setting. The results of the field assessment were compiled and correlated against the GRMP Risk Level rating system, comprising a Probability Factor and a Consequence Factor. From the results of this comparison, select condition assessment tools were short-listed for use based on their effective correlation with the GRMP rating system components. Three of the rockfall geohazard sites included in the study had pre-existing remote sensing databases. This information was built upon, and change detection analysis was performed as a means to quantify each slope’s performance. The shortlisted condition assessment results of these three slopes were then compared to two performance metrics derived from the change detection results. The selected performance metrics were the estimated annual failure volumes and frequency of events greater than or equal to 1 m3 from failure volume-frequency plots developed for each site.
  From the results presented in this thesis, the GRMP rating system was determined to be a viable condition assessment tool as part of the formalized GAM program. The GRMP rating system components correlated well with industry accepted and rigorously tested slope rating and rock mass rating systems such as the Rockfall Hazard Rating System (RHRS), Q-Slope, and Geological Strength Index (GSI). Strong correlations were subsequently developed between these short-listed condition assessment tools and the rockfall metrics derived from the change detection results. A practicable and repeatable methodology was successfully developed to directly compare the results of condition assessment tools with the results of rock slope performance monitoring techniques. The analysis presented in this thesis provides a basis for which TEC, or other transportation agencies, can build upon with data from additional rockfall geohazards to improve the prioritization of maintenance and remedial measures, based on a quantified level of hazard.

• Subjects / Keywords

  • Geotechnical Engineering
  • Change Detection
  • Geohazards
  • Rock Slopes
  • Geotechnical Asset Management

• Graduation date

  Fall 2023

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-ca7v-y680

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.