2023
Bleadon, North Somerset
Edenstone
Abcas Ltd
N/A
Rockfall Protection at Bleadon Quarry Stabilised Netting Solution for Residential Development
Challenge
In 2022, housing developer Edenstone Homes purchased Bleadon Quarry from Marshalls with plans to construct 42 new residential properties within the former quarry site. While the redevelopment offered significant opportunities, it also introduced a major geotechnical challenge due to the presence of exposed limestone quarry faces surrounding the development.
The weathered rock faces presented a high risk of rockfall, with loose surficial material and potentially large rock blocks capable of detaching and falling onto the planned housing area. This created a critical safety concern for both property and future residents, requiring an effective and long-term rockfall protection solution.
Given the nature of the hazard, a stabilised rockfall netting system was identified as the most appropriate method of slope stabilisation. The system needed to provide high tensile strength, low deformation performance, and reliable containment of unstable rock material when combined with rock anchors.
Solution
To address the rockfall risk at Bleadon Quarry, designers at Hydrock selected Maccaferri’s Steelgrid® HR30, a high-performance stabilised netting system specifically engineered for slope stabilisation and rockfall mitigation.
Steelgrid® HR30 is an advanced composite mesh that combines double-twisted steel wire hexagonal mesh with integrated high tensile steel cables. These cables are woven into the mesh during manufacturing, creating a reinforced structure with exceptional strength, stiffness, and durability.
The innovative production process enhances traditional double-twist mesh by incorporating both full and half-hexagonal apertures. This configuration allows the steel cables to remain predominantly straight within the mesh, delivering high tensile resistance and superior punching resistance at low strain. As a result, the system provides immediate load resistance without the need for pre-tensioning, improving installation efficiency while maintaining high performance.
When installed as part of a stabilised netting system, Steelgrid® HR30 works in conjunction with rock anchors to secure loose material directly against the slope. In the event of rock detachment, the mesh responds immediately, limiting movement and preventing debris from falling. Compared to conventional double-twist rockfall netting, Steelgrid® HR30 offers significantly lower elongation of just 5–7%, versus 16–23%, and delivers 20–40% higher punching resistance. This results in reduced deformation and improved slope stability.
The system is supplied as a complete rockfall protection solution, including specialist anchor plates with clawed corners that securely grip the high tensile cables, ensuring close contact between the mesh and the rock face. Additional components, such as HR Grips and HR Links, support a system-based installation approach in line with CIRIA C775 guidelines for rock netting design, installation, and long-term management.
For enhanced durability, Steelgrid® HR30 features Class A Zn-Al 5% GalMac® corrosion protection, making it suitable for long-term use in demanding environments. Where required, an additional Polimac® polymer coating can be applied, extending the design life to over 120 years and ensuring robust performance in aggressive environmental conditions.
Used Products
