Numerical analysis of the performance of wire mesh and cable net rockfall protection systems

Abstract Wire mesh and cable net systems have long been used to control rockfall on actively eroding slopes. The design of these systems has been primarily based on empirical methods, engineering judgment, and experience; their performance has been mixed. There is a general consensus among specialists that in wire mesh systems that have functioned well some elements may be over-designed or even unnecessary. On the contrary, system failures under a variety of loading conditions have occurred within the last few decades, indicating that certain design elements may in fact be under-designed for their desired application. This study presents the results of finite element analyses conducted to examine the performance of the individual elements as well as the overall stability of the wire mesh systems. The load–displacement behaviors of widely used fabrics were determined in the laboratory. The friction between the mesh and rock can be a major contributor to the stability of the wire mesh and cable net systems. The interface friction is controlled by macro and micro roughness of the surface. Interface friction is a difficult parameter to quantify in practice. Guidelines are provided to estimate this parameter from observed slope irregularity and surface roughness based on finite element analyses. The top horizontal rope is an essential element in the design of wire mesh and cable mesh systems. The study also shows that the inclusion of interior horizontal support ropes does not reduce the stress within the mesh, and accordingly, provides no mechanical benefit. Results show that the use of vertical ropes eliminates stress concentration around the anchor support and reduces stresses on the top horizontal rope provided that they are clamped to the mesh at closed intervals.