ROCKFALL MITIGATION MEASURES FOR PEACOCK PROJECT, RABALE

After studying the geological and topographical details, suitable rockfall mitigation solutions were devised to contain rocks falling from the face. To protect the area from falling rock debris, simple drapery system is proposed along with top nails and bottom nails (HYSD bars 25 mm dia., 3-4m long spaced at 1.5m c/c) and anchor fasteners on rock slope to contain loose and falling debris. Secured drapery system with mesh, wire ropes in diagonal fashion and raster of surface nails (HYSD bars 25 mm dia., 4 m long at 2.5m c/c spacing in both directions) is considered where surficial instabilities are observed. A fence of 3.5m has been constructed at toe and hence the bottom anchoring was terminated above the fence top line. Because of the proximity of the walkway to cut slope, the meshes selected need to adhere to the slope surface and should have high strength at low strain. Maccaferri Steelgrid MO was selected as the mesh for the simple and secured drapery systems to satisfy this requirement. Steelgrid MO offers cost effectiveness, ease of installation and a proven track record as well. The MacRO1 and MacRO 2 were used to design the secured and simple drapery system respectively. Subsurface drainage system has been implemented by using 4m long perforated PVC pipe (lined with non-woven Geotextile) of 50 mm internal dia. spaced at 3m c/c spacing in longitudinal direction (in 3-5 rows).