From concept to reality, combining a rockfall barrier with a retaining wall to protect railway tracks

ABSTRACT: At a railyard in Hamilton, Ontario a slope needed to be cut and a retaining wall installed as part of the capacity improvement program. In addition to stabilizing the cut slope above the location of the proposed retaining wall a rockfall source area was identified. The hazard of rocks falling down the slope and over the retaining wall was very real. Canadian National Railway (CN) approached Geobrugg and inquired if there was any experience in combining rockfall protection with retaining walls. Geobrugg responded with conceptual level options to combine the retaining wall and a flexible rockfall barrier. A consultant performed a rockfall evaluation and determined a site specific rockfall energy and bounce height. With this Geobrugg provided the anticipated system forces on the posts that would occur during the design impact. The ‘H’-piles used in the soilder beam and lagging retaining wall were then dimensioned above the top of the wall grade to accommodate the rockfall barrier system. The retaining wall was constructed and a rockfall net system was provided and attached to the extended ‘H’-Piles. In areas where the retaining wall was no longer required, a traditional rigid post rockfall protection system was installed.