Active Slope & Rockfall Protection Drapery Net System
Wire rope net drapery mesh systems are a very viable solution when large rocks must be prevented from falling dangerously, and catchments such as passive rockfall barriers are not practical. Rockfall fences may prove impractical due to space limitations at the slope toe, unusually high rock bounce heights, or extremely steep slopes. When rocks greater than 0.6 m in diameter need to be retained by draping, wire rope nets become the material of choice over wire mesh and chain link mesh materials. Draped systems utilizing wire rope nets have the advantage of being capable of bearing large static loads (from rocks, debris, snow or ice) and being highly resistant to tearing, while conforming to irregular terrain and allowing vegetation to take hold.
The basic wire rope net slope protection system utilizes a series of individual wire rope nets laid onto a slope, each net having typical dimensions of 3 x 6 m (10 x 20 ft) and a mesh size of 0.3 x 0.3 m (12 x 12 inch). The nets can either be laced to anchored support ropes hanging freely down the slope, or the nets can be anchored at each corner or to existing rockbolt locations. The former design, also referred to as a blanket system, produces what is essentially a controlled rockfall, allowing rocks to slowly and safely move downslope under the nets. The latter design is intended to hold all rocks in place and allow no movement. Smaller mesh sizes can also be manufactured, and/or chainlink fence material can be attached to catch rubble smaller than the net mesh size.
