Rockfall protection embankments
The rockfall embankment works are constituted by an earth structure with a trapezoidal geometry, often combined with the presence of a rocktrap coated by a low elastic restitution coefficient material (eg. sand). For the sizing of the work are carried out the usual assessments provided for works of loose materials, ie the calculation of the bearing capacity of the foundatoin ground, the settlements of the foundation ground and the stability calculation of the two sides upstream and downstream.
The work acts as an overload on the slope altering the overall stress distribution in the soil. It is therefore necessary to check the influence of the embankment on the overall stability of the slope through the usual limit equilibrium analysis.
Unlike elastic rockfall barriers, an embankment dissipates the impact kinetic energy of the boulder through the work that the boulder itself must make to penetrate the soil structure. It should be then calculated the penetration depth of the rock block and verified that it is less than the thickness of the work. Otherwise the artifact should be considered undersized. The depth of penetration is assessed with the relationship of Kar (1978), in the case of direct impact with the earthy material.