Rockfall protection embankments consist of an earth structure with a trapezoidal geometry, often combined with a ditch (rocktrap) lined with material having a low coefficient of elastic restitution (e.g., sand). For the sizing of the structure, the standard evaluations for loose material earthworks are carried out, namely the calculation of the bearing capacity of the foundation soil, its settlements, and the stability calculation of the upslope and downslope sides.
Rockfall protection embankments – RPE – GeoStru
The structure also acts as a surcharge load on the slope, altering the general stress distribution in the soil. It is therefore necessary to verify the influence of the embankment on the global slope stability using standard limit equilibrium analysis procedures.
Unlike elastic rockfall barriers, an earth berm dissipates the kinetic impact energy of the boulder through the work the boulder itself must perform to penetrate the earth structure. Therefore, the penetration depth of the rock block must be calculated and verified to be less than the thickness of the structure.
Otherwise, the structure must be considered undersized. The penetration depth is evaluated using Kar’s (1978) relationship, in the case of direct impact with the earthen material.