Project Overview

This field safety report reviews a successful installation project near Lyon, France, designed to protect a busy local road from dangerous seasonal rockfalls.

Step 1: Evaluating the Debris Risk

The regional mountain route outside Lyon suffered from severe shale weathering. Small rockfalls occurred every spring, dropping stones weighing between 50 kg and 200 kg directly onto the active roadway. The local highway agency required an immediate, low-maintenance catch barrier that could take repeated impact loads within a narrow roadside clearance zone.

Step 2: Sourcing the Structural Specifications

Engineers deployed a multi-tier protection bund at the toe of the slope using our heavy-duty gabion baskets.

Mesh Structure: Woven double-twisted hexagonal wire mesh that prevents unraveling if a single wire breaks.

Double Protection: Galfan zinc-aluminum alloy plus a thick, UV-stabilized PVC coating for maximum resistance against winter de-icing salts.

Wire Gauges: 2.7 mm inner steel wire which reaches 3.7 mm total diameter after the smooth PVC application.

Mesh Aperture: 60 by 80 mm spacing to capture small rock fragments and prevent mesh punctures.

Box Sizing: Heavy 4.0m x 1.0m x 1.0m units to provide massive structural ballast.

Step 3: Deployment Metrics and Performance

The safety barrier was erected as a standalone gravity wall along the road edge. Internal wire ties and diaphragm partitions were added every meter to prevent bulging during high-energy stone impacts.

The total barrier length reached 300 linear meters with a structural height of 2.0 meters, formed by two layers of stacked wire cages over a 1.0-meter base depth. The system provides a high mechanical tensile strength of 45 to 50 kilonewtons per meter.

Key Project Results:

1.Zero Damage: It successfully caught 14 metric tons of falling rock in its first year without any damage.

2.Impact Absorption: The double-twisted wire prevents structural failure by spreading heavy impact forces across the gabion baskets.

3.Weather Proof: A specialized PVC coating completely shields the steel wire from rust, moisture, and mountain frost.

4.Natural Green Look: Wild grass grew over the stone-filled baskets, turning the safety barrier into a beautiful, eco-friendly landscape.