Procedures to Develop Defined Metrics and Protocols Using Existing Rockslope and Rockfall Design Guidelines within Corridors for Mitigation of Rockfall and Rockslides

Randy PostResearch Needs Statements

Crews remove the large boulder that fell in the rock fence along the side of I-90 over Snoqualmie Pass in Washington State. Image credit WSDOT.

Rockfall and rock slope design engineering guidelines have been established since the 1960’s with such notable works as the Ritchie Ditch Catchment (1963), Rock Slope Engineering (Hoek and Bray, 1974), Rockfall Catchment Area Design Guide (FHWA-OR-RD-02-04), and more recently Rockfall Characterization and Control (Transportation Research Board (TRB), 2012). These guidelines offer the basis for design of rock slopes and rockfall catchment but do not establish guidelines, criteria, or metrics for implementation that designers or agencies can follow.

Given the desire to make and communicate asset management based design decisions, and to design for resilience and the consideration of life-cycle cost, there is a need to develop a rock slope and rockfall guideline metric and framework that establishes suggested parameters and protocols based on:

Rock slope evaluation to determine potential for generating rockfall by either a condition, tolerable risk, or performance based systems or combinations therein,

Rock slope mitigation options such as blasting methods, stabilization, or protection measures or combinations of each to reduce the potential for rockfall,

Ditch catchment options based on rock slope evaluation, mitigation options and traffic volumes,

Formulating an iterative life-cycle process to evaluate and encompass roadway design, constructability, environmental, cost, maintenance, and other considerations using the previous points including potential for rock slope to generate rockfall, mitigation options, and ditch catchment requirements,

Results of the research will be useful to transportation agencies charged with managing rockfall hazards.

RNS last updated on May 5, 2016.  Visit the TRB website to view the full RNS.