Simulation and Statistical Analysis of Motion Behavior of a Single Rockfall

The impact force of a rockfall is mainly determined by its moving behavior and velocity, which are conting e t on the rock shape, slope gradient, height, and surface roughnes s of the moving path. It is essential to precisely calculate the mo ving path of the rockfall in order to effectively minimize and preve nt damages caused by the rockfall. By applying the Colorado Rockfall Simulation Program (CRSP) program as the analysis tool, this r esearch studies the influence of three shapes of rock (spherical, cylin drical and discoidal) and surface roughness on the moving path of a singl e rockfall. As revealed in the analysis, in addition to the slope gradient, the geometry of the falling rock and joint roughness coefficient ( JRC ) of the slope are the main factors affecting the moving behavior of a rockfall. On a single flat slope, both the rock’s bounce height an d moving velocity increase as the surface gradient increases, with a critical gradient value of 1:1 m = . Bouncing behavior and faster moving velocity occu r more easily when the rock geometry is more oval. A flat piece tends to cause sliding behavior and is easily influenced by the ch ange of surface undulation. When 1.4 JRC < the moving velocity decreases and the bounce height increases as JRC increases. If the gradient is fixed, when JRC is greater, the bounce height will be higher, whil e the moving velocity will experience a downward trend. T herefore, the best protecting point and facilities can be chosen if th e moving paths of rockfalls are precisely estimated. Keywords—rock shape, surface roughness, moving path.