Ground reinforced embankments for rockfall protection: design and evaluation of full scale tests

Abstract

Infrastructures such as roads and railways as well as urbanised areas, in mountainside regions, can frequently be endangered by rockfalls and, therefore, need to be protected against the impact of rolling blocks. Among the various protection works that can be used, ground reinforced embankments can be considered a feasible technique. A set of full-scale tests on embankments made of ground reinforced by geogrids are presented and discussed. The experiments were performed in a specifically designed and constructed test facility, where concrete blocks up to 9,000 kg in weight were thrown onto a geogrid reinforced embankment at a speed of about 30 m/s. Several embankments made of different geogrid types, different soils and construction layouts were tested at different impact energy levels, permitting a quantitative assessment of the resistance impact of these structures. The experimental results were compared with those obtained from a dynamic finite element method numerical model, and a good agreement was obtained.

Real-scale investigation of the kinematic response of a rockfall protection embankment

“…For impact energies around 1000 kJ, the maximum deformation measured on structures tested by Maegawa et al (2011) was three times greater than that for cellular walls (our study). For impacts involving 2000 kJ kinetic energy projectiles, the latter type of structure performed similarly to structures tested by Peila et al (2000Peila et al ( , 2007 in terms of penetration.…”

“…Despite this variability, these experiments globally provide a valuable database for comparison with the results presented in this paper. For this purpose, a representative panel of experiments from Hearn et al (1996), Yoshida (1999), Peila et al (2000Peila et al ( , 2007, Sung et al (2008) Peila et al (2000Peila et al ( , 2007 4.2 0.9/5 2500 600 Burroughs et al (1993) 3.1 1.8/1.8 1400 900 Maegawa et al (2011) 4.2 2.2/4.3 2037 1730…”

“…In particular, real-scale experiments on embankments with impact energies higher than 1000 kJ have been conducted by different authors (Burroughs et al, 1993;Hearn et al, 1995Hearn et al, , 1996Yoshida, 1999;Peila et al, 2000Peila et al, , 2007Maegawa et al, 2011). Impact experiments on real-scale structures have also investigated lower-energy rockfall Sung et al, 2008).…”

Impact of rockfalls on protection measures: an experimental approach

“…The maximum impact force (F m ) is, therefore, crucial during designing the protection measures. In the literature, the F m has been found to be affected by factors, such as platform on the slope, physical and mechanical properties of falling materials, and incident angle when collision happens (Jean and Pascal, 2005;Azzoni et al, 1995;Tetsuya, 2004;Peila et al, 2007). Jean and Pascal (2005) carried out experiments and indicated that the drop height is the most important factor influencing the F m .…”

Improvements of safety conditions of unstable rock slopes through the use of explosives

“…Therefore for a rockfall protection design to be successful it is necessary first to define the area of risk located below the unstable rock slope (Evans and Hungr, 1993;Crosta and Agliardi, 2003;Guzzetti et al, 2003;Locatelli, 2005) and to forecast of the possible trajectories of the falling blocks (Giani, 1992) and secondly to chose and design the correct method that can: stabilize the unstable rock block directly on the slopes (Peckover and Kerr, 1977;Giani, 1992, Duncan andNorman, 1996;Oggeri and Peila, 2000), stop an already moving block or blocks through technological devices mainly located at the bottom of the slope (Peila et al, 1998(Peila et al, , 2006(Peila et al, , 2007Pelizza et al, 2004), or conduct operations to remove the unstable elements (Cardu et al, 2004;DeWall, 1996;Goumans and Wallace, 1999;Philippon, 2001;Woolf and Goumans, 2002;Mackenzie, 2004).…”