A Validation of Failure Modes and Yield Accelerations of Rock Blocks Subjected to Seismic Loads

Frankie Johnston, Mary MacLaughlin, Department of Geological Engineering, Montana Tech, 1300 West Park Street, Butte MT 59701

Rockfalls caused by seismic (earthquake) events can be very unpredictable and may lead to loss of life and damage to property. Since it is natural for blocks of specific geometries to fail in certain ways, it is possible to classify them based on their shape and predict their failure mode. Under static conditions, this is well understood and can be analyzed through methods such as steronets and kinematic analysis. The behavior of rock blocks subjected to seismic accelerations is less understood and only beginning to be explored. In the 2018 study “Pseudo-static failure modes and yield accelerations in rock slopes,” Matthew Gibson describes a methodology and accompanying diagram he developed to categorize the theoretical behavior of parallelograms (representing rock blocks) based on their forward and backward angle. This study aims to validate the theoretical models proposed by Dr. Gibson by performing a laboratory investigation, to supplement the verification he performed using computer models. The experimental study will be accomplished by: 1) creating blocks based on Gibson’s two dimensional models with three dimensional printing material, 2) using Montana Tech’s shake table to subject the blocks to increasingly higher accelerations until failure (sliding, slumping, or toppling) is observed, and 3) recording the data with accelerometers and a high-speed video camera. Conclusions will be drawn based on the agreement of the laboratory investigation with Dr. Gibson’s predictions. We have defined that satisfactory validation will be achieved if a minimum of 90 percent of the failure modes observed in the laboratory experiments agree with the predicted failure modes, and the yield accelerations for the blocks as determined in the laboratory experiments are within 10 percent of the predicted yield accelerations. We also expect to gain additional insight regarding the behavior of rock blocks during earthquakes during the course of this experimental research.

Additional Abstract Information

Presenter: Frankie Johnston

Institution: Montana Technological University

Type: Poster

Subject: Engineering

Status: Approved

Time and Location

Session: Poster 6
Date/Time: Tue 2:00pm-3:00pm
Session Number: 4573