Treatment and maintenance of rock slopes on transportation routes

Abstract

Unstable rock slopes along transportation routes in rocky terrain are hazards requiring carefully selected maintenance techniques if safety against rock falls is to be improved at reasonable cost. The paper reviews the causes of rock falls and methods of dealing with them in North American and European highway and railway practice. Methods are classified as those that: (a) stabilize slopes or prevent rocks from moving out of place, (b) protect the right-of-way by keeping rocks that do move out of place from reaching the roadway, and (c) warn or signal traffic when rocks arrive at the vicinity of the roadway. Methods of stabilization, protection, and warning are described and illustrated. Some of these methods can be combined for increased safety at a single site. Guidelines are suggested to organize an effective program to guard against rock falls. Steps in planning, deciding on the priority of sites to be treated, and choice of treatment methods at particular sites are all discussed. Desirable records and measurements are outlined. The paper is intended to be a practical reference for practising engineers.

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

“…These seven causes together account for about 70% of the rockfalls as was observes by California Department of Transportation which made a comprehensive study of rockfalls that occurred on the state highway system (McCauley, 1985). These results were confirmed by other authors such as Duncan and Norman (1996), Peckover and Kerr (1977), Giani (1992), and Wieczorek et al (2008). The other major group of factors affecting stability are the geologic and geotechnical conditions at each site, namely, fractured rock, adverse dip of the joints and soil…”

“…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).…”

Technical Note: Design of rockfall net fences and the new ETAG 027 European guideline

“…These solutions can either prevent the blocks from breaking off the rock walls, thus reducing the frequency of the collapses, or control, intercept or deviate the blocks during their movement. These latter devices include ditches, rockfall shelters, ground embankments and net fences made of metallic meshes (Peckover and Kerr, 1977;Peila et al, 2007).…”

Design of reinforced ground embankments used for rockfall protection

“…1), both in civil and in mining applications, in order to protect roads, inhabited areas, quarry plants or yards. Different embankment types (Table 1) made of natural compacted soil, huge rock blocks, gabions or reinforced ground have been used (Peckover and Kerr, 1977;Giani, 1992;Wyllie and Norrish, 1996;Oggeri and Peila, 2000;Nomura et al, 2002;Peila et al, 2007). The most frequent examples are reinforced embankments.…”