BRITE Relaunch: Developing Material-Informed Rockfall Coefficients of Restitution Through Soil Characterization and Instrumented Slopes

This Boosting Research Ideas for Transformative and Equitable Advances in Engineering (BRITE) Relaunch award will fund research that focuses on developing rockfall coefficients of restitution based on field properties of slope materials. Rockfalls are a serious concern in mountainous areas; they damage infrastructure and cause indirect economic losses such as increased travel times. During a rockfall event, a rock becomes detached from a slope, freefalls, impacts the ground, and moves downslope by bouncing, rolling, and sliding. When the rock impacts the ground, the speed with which it moves after the impact is thought to be a function of the rock and ground material properties. Having reliable coefficient of restitution values is important because they are used to predict how far the falling rocks will move down a slope. The specific goal of this research is to develop coefficients of restitution that are based on material properties rather than empirically derived coefficients of restitution that are extensively used in rockfall studies. Rockfall experiments will be performed by dropping concrete blocks of different shapes and sizes on soil slopes instrumented with force sensors and constructed with materials of known properties. Pre-test aerial imaging will be used to assess the geometry and roughness of the soil slopes. During the tests, aerial- and ground-based cameras will be used to track the paths of the concrete blocks. The collected data will be used to develop material-informed coefficients of restitution. Back analyses will be performed on natural rockfall sites using the developed material-informed coefficients of restitution relationships to investigate if they provide a better estimate of rockfall runouts than the empirical coefficient of restitution values. The overarching focus will be on developing a better understanding of how material and slope properties influence rockfall coefficient of restitution values and if slope parameters must be incorporated into the development of material-informed coefficient of restation relationships. This project will allow the PI to fill in the knowledge gaps in laboratory-, bench-, and field-scale rockfall studies to develop meaningful and realistic values for rockfall coefficients of restitution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.