The robust SPIDER® spiral net of high-tensile 4 mm steel wire strand secures loose rocks, rock spurs and overhangs, also unstable rock formations with a very irregular surface structure and coarse block weathering. SPIDER® stabilizes large areas of rock with a nail grid and boundary ropes. Isolated unstable blocks are wrapped with the spiral net and anchored all around with boundary ropes.
Components
The SPIDER® rock protection system consists of the SPIDER® spiral rope net, nails and anchors, spike plates as standard anchorage, border and temporary ropes and net connection elements.
Dimensioning
The SPIDER® protection measures are dimensioned with the determined rock stress analysis parameters and the
RUVOLUM® ROCK dimensioning software. This software is available online on request.
Tests
Large scale field tests confirmed the practical suitability of the SPIDER®spiral rope system. They enabled to investigate under the most realistic conditions the supporting behavior of the rock protection system, the interaction between the system components and the direction, also the level of the forces transferred from the unstable block via the net into the individual anchorage points in a 1:1 scale under different boundary conditions.
Installation
SPIDER® is installed in rolls of 3.5 x 20 m. By means of SPIDER® spike plates the spiral net can be stretched over edges and rock spurs with rock nails or rock anchors, or anchored in hollows and niches – depending on the nature of the rock, together with a fine secondary mesh.
Benefits
compared with anchor bars, shotcrete coverings or wire rope nets with rope bracing:
- free choice of anchor points
- fast mounting of the spiral rope net rolls over large areas
- suitable for reinforcing existing protection measures