Geotechnical Engineering

WSDOT Developing and Calibrating Fragmental Rockfall Models

Managing rock slopes adjacent to highway infrastructure requires considering possible slope instability and designing mitigation efforts to prevent rockfall damage to the roadway and travelers. When engineers design a slope scaling program, rockfall catchment area, or rockfall barrier, they generally use a rockfall simulation model to predict the potential path and distribution of falling rocks. However, current 2D models tend to significantly overestimate the length of falling blocks’ travel paths, which leads to more expensive and extensive protection than required for slope maintenance. Recent studies have demonstrated that rockfall models built in game engine environments can replicate the observed pathways and fragmentation sizes of rockfall events. The ultimate goal of this pooled fund study, led by WSDOT, is to develop “game-engine”-based  3D rockfall simulation software, based on data from LiDAR or photogrammetry models, that has the potential to more realistically model rockfall fragmentation and large block interaction.

Transportation Pooled Fund details

Principal Investigators:
Joseph Wartman, Civil and Environmental Engineering, UW
Jean Hutchinson, Geological Science and Engineering, Queen’s University
Michael Olsen, Civil and Construction Engineering, Oregon State University

Sponsors: WSDOT
with pooled funds from Alaska, Arizona, California, Colorado, New York, Tennessee, and Texas
WSDOT Technical Monitor: Marc Fish
WSDOT Project Manager: Jon Peterson
Scheduled completion; December 2023

Update to WSliq Software for Soil Liquefaction Hazard Evaluation

This project is updating and extending the capabilities of a computer program, WSliq, for evaluating soil liquefaction hazards.  Probabilistic liquefaction hazard analysis (PLHA), developed previously for WSDOT and implemented in WSliq, has been recognized as an improved procedure for evaluating potential hazards from liquefaction.  PLHA considers all peak ground surface acceleration and magnitude levels based on site-specific ground motion hazard data and weights the contributions of all according to their joint probability of occurrence.  In doing so, it considers all possible earthquake scenarios and allows designs based on consistent likelihoods of triggering at all locations within the state. Because a number of changes have occurred in the geotechnical profession’s understanding and treatment of liquefaction since the development of WSliq, this project is developing, implementing, and testing new PLHA procedures and updating the WSliq program to incorporate the resulting improvements.

Principal Investigator: Steven Kramer, Civil and Environmental Engineering, UW
Sponsor: WSDOT
WSDOT Technical Monitor: Tony Allen
WSDOT Project Manager: Jon Peterson
Scheduled completion: December 2023