Comprehensive knowledge of gabion mesh

I. Origin and Development

The origin of gabion mesh can be traced back to over 2,000 years ago during the Pre-Qin period in China. The bamboo weaving gabion used in the Dujiangyan Project was its prototype. Modern gabion mesh was industrially produced in Europe in the 19th century and was initially used for reinforcing railway subgrades. In the late 20th century, with the development of hot-dip galvanizing, Galfan (zinc-aluminum alloy) and plastic coating processes, its corrosion resistance was greatly improved and it was gradually widely used in water conservancy, transportation and other fields.

Ii. Core Materials and Craftsmanship

(1) Material classification

1.Hot-dip galvanized steel wire: Zinc coating thickness ≥245g/m², suitable for ordinary environments, service life 10-20 years.

2.Galfan (zinc-5% aluminum-mixed rare earth alloy) : Its corrosion resistance is more than three times that of hot-dip galvanizing, with a service life of 50-60 years. It is the first choice for coastal areas and chemical industrial zones.

3.Plastic-coated steel wire: Galvanized layer covered with 1.0mm PVC, resistant to acid and alkali (pH3-11), with a service life of over 15 years in C5 grade highly corrosive environments.

4.Stainless steel: 316L material is suitable for highly corrosive scenarios (such as seawater), with a lifespan of over 50 years.

(II) Weaving Techniques

The double-twisted hexagonal mesh process is adopted, with each node twisted 4 to 6 times. The shear force resistance reaches 1.6kN, and the allowable deviation of the mesh size is ≤±4% or ±2mm (taking the larger value). The diameter of the edge wire is 0.5-1.0mm thicker than that of the mesh wire, enhancing the overall strength.

Iii. Classification and Specifications

(1) Classification by structure

1.Gabion cages: height 0.15-2.0 meters, length 1-6 meters, width 0.5-3 meters, used for retaining walls and DAMS.

2.Gabion mesh pad (Reno mattress) : Thickness 0.15-0.5 meters, area 2-6 square meters, suitable for slope protection and riverbed bottom paving.

3.Welded gabion mesh: After being welded into shape, it is assembled with binding wire. It has a low cost but poor flexibility and is suitable for temporary projects.

4.Reinforced gabion mesh: The diameter of the reinforcing wire on the mesh surface is greater than or equal to that of the edge wire, with strong anti-deformation ability, and is used for high-fill roadbeds.

(II) Standards for Filling Materials

Particle size: Minimum particle size ≥ 1.5 times the mesh size (for example, 80mm mesh requires ≥120mm stone material), maximum particle size ≤ 2/3 of the minimum structural size (for example, 1m high net box ≤0.67m).

Strength: Compressive strength ≥30MPa. Polygonal block stones are preferred due to their good interlocking properties.

Iv. Application Fields

(1) Water conservancy projects

1.River management: To resist the erosion of 3m/s water flow, for instance, ecological gabion nets are used for the embankment protection of the Huangshi section of the Yangtze River, which takes into account both flood control and greening.

2.Coastal protection: The slope of the coastal road in Qingdao uses C5 grade plastic-coated gabion mesh, which has no rust for 5 years and reduces maintenance costs by 70%.

3.Reservoir project: Diversion DAMS guide floods, and spillway DAMS dissipate energy to prevent erosion.

(2) Transportation Engineering

1.Highway and railway: For high slopes of expressways (≥60°), Galfan gabion nets are used in combination with grass planting to achieve the integration of protection and landscape.

2.Bridge protection: Gabion mesh pads are laid around the bridge piers to prevent water from washing away them.

(3) Ecological Engineering

1.Mountain greening: In a project in a mountainous area of Henan Province, the vegetation coverage rate of gabion nets reached 70% within six months, forming a stable structure of 'net - stone - plant'.

2.Mine restoration: Acid-resistant plastic-coated gabion mesh used in the coal mine's waste dump in Shanxi Province has remained corrosion-free for three years, with a vegetation survival rate of 85%.

(4) Municipal engineering

1.Landscape retaining wall: Green plastic-coated gabion mesh is used for urban rivers, which is in harmony with the surrounding environment. Gabion mesh is recommended when the height is ≤3 meters.

2.Flood control and emergency response: Ordinary hot-dip galvanized gabion mesh is used for temporary water retaining walls in rural areas, which is easy to assemble and has a low cost.

V. Core Performance Advantages

1.Flexible structure: It can adapt to uneven settlement of the foundation, does not crack as a whole, and has outstanding seismic performance.

2.Strong water permeability: Porosity 25%-40%, reduces groundwater pressure and prevents damage from hydrostatic pressure.

3.Eco-friendly: The mesh retains soil and seeds, and plant roots penetrate to form a biological protective layer.

4.Corrosion resistance: The Galfan + plastic-coated composite process ensures a service life of over 120 years in highly corrosive environments.

5.Economy: The construction cost is 30% to 50% lower than that of concrete, and the maintenance requirements are less.

Vi. Technical Parameters and Selection

(1) Key Indicators

(II) Selection Suggestions

1.Project scale: For retaining wall height ≥3m or coverage area ≥1000㎡, select gabion mesh (five-twist process), and for small-scale projects, use gabion mesh.

2.Environmental conditions: For coastal or chemical industrial areas, select Galfan or C5 grade plastic-coated gabion mesh. For inland ordinary environments, use hot-dip galvanized gabion mesh.

3.Functional requirements: For strong impact resistance, choose reinforced gabion mesh. For ecological greening, prioritize the combination of net pads and grass planting.

Vii. Key Points of Construction

1.Foundation treatment: Level and compact the foundation. For weak foundations, a crushed stone cushion layer or concrete foundation should be laid.

2.Assembly specifications: The cages should be bound with binding wire, with a spacing of no more than 20cm. Adjacent cages should be arranged in a staggered manner.

3.Filling requirements: Stone materials should be filled in layers, with 5-10cm reserved on the top surface for covering soil, which can be used for sowing or laying turf.

4.Vegetation maintenance: Regularly water at the initial stage and select native drought-tolerant plants (such as sea buckthorn and alfalfa), increasing the survival rate to over 85%.

Viii. Maintenance and Lifespan

1.Daily inspection: Inspect the rusting of the net body and the loosening of the stone materials annually, and replace the damaged parts in a timely manner.

2.Service life: 5 to 20 years for ordinary hot-dip galvanized gabion mesh, 20 to 60 years for Galfan gabion mesh, and 15 to 120 years for plastic-coated gabion mesh (depending on the environment).

Ix. Standards and Norms

International standards: EN 10223-3 (steel wire), EN ISO 12944 (anti-corrosion grade).

Chinese standards: YB/T 4190-2018 (Gabion mesh), GB/T 20492 (zinc-aluminum alloy coating).