Flood Defence Scheme, Lisburn, Belfast

• Client: Translink
• Contractor: McLaughlin and Harvey
• Consultant: Amey Consulting
• Gripple Terra-Lock™ System: TL-P2 Pins, TL-A3 Anchors and TL-406 Plates

The Gripple Terra-Lock™ System was used on a flood defence scheme, preventing erosion on a rail network embankment in Lisburn, Belfast. With no heavy machinery required during install, the system allowed the contractors to work alongside a live rail network with little disruption to the train service.

The Terra-Lock System gains its stability by coupling key engineering principles with specifically designed products to successfully utilise the natural properties of on-site materials. Gripple’s innovative ‘grip’ and ‘pull’ technology is complemented by anchor systems and TRM (Turf Reinforcement Matting) to deliver a comprehensive, trusted solution.

TL-P2 Pins were used initially to pin down the TRM, allowing for an intimate contact between the mat and the ground. This in-turn allows vegetation to grow, maintaining a natural and green aesthetic, and helps to mimic the effects of grass before roots establish. The TRM reduces surface erosion from water and air, helping to alleviate the risk of flood damage to the rail line. The pins are installed using a general-purpose Combi 18v drill, with a bespoke Chuck provided by Gripple. Following this, TL-A3 Anchors in conjunction with TL-406 Plates were installed to prevent pre-filled rock mattresses from falling down the slope. The TL-A3 Anchors transfer shear forces deep into the ground to ensure a secure and stable system. The Anchors were installed using the Gripple Petrol Driver, allowing installation to the required depth and locked using the JackJaw, which then was used to remove the Drive Tool.

The benefit of using Gripple here allowed the use of products with the in-situ slope profile, meaning minimal disturbance to the train line and maintaining a natural-looking environment. The system benefits mean that the clients were able to take advantage of a green solution, making use of on-site material, minimising transport and related emissions, the efficient installation meant that the system could be quickly installed and vastly reduced time spent on-site, as well as providing a durable, erosion-resistant solution.