ROCKFALL EVALUATION BY COMPUTER SIMULATION

A 4-mi section of Interstate 40 in the western part of North Carolina is undergoing a major improvement to reduce the risk of damage caused by landslides and rockfall. A major concern is the effectiveness of measures taken to keep rockfall material out of the way of travel. By using a probabilistic approach, a model was developed for predicting the distance that bouncing rocks will travel down a slope. Field data on rock bounce characteristics were used to compute the coefficient of restitution. A computer program called "ROCKSIM" was produced to predict rockfall impact areas by using the coefficient of restitution and kinematics of free-fall and rolling motion. The ROCKSIM predictions were used to evaluate the effectiveness of the proposed remedial measure to mitigate the hazard. This preliminary application indicated that ROCKSIM may be a useful tool for evaluating the rockfall process in other areas. Additional data will be collected for model calibration.