The stabilisation of onshore wind farm infrastructure involves the process of constructing and reinforcing access tracks, crane hardstandings and turbine foundation platforms on weak, peaty or soft subsoils. Soft upland ground and heavy plant delivery loads can cause rutting and subgrade failure. Secugrid® geogrids and Combigrid® composite products solve this challenge through load distribution and integrated filtration.
Naue products are deployed wherever bearing capacity, durability and cost-efficiency are critical in wind farm construction.
Reinforce haul roads and access routes across soft upland terrain
Stable hardstandings for turbine erection cranes on weak subgrades
Load-bearing preparation for turbine base foundations on peat
Permanent reinforced roads serving wind farm substations and maintenance access
Protect cut-and-fill slopes against erosion during and after construction
Wind farm construction demands products that perform under extreme installation stress. Heavy plant, crane vehicles and turbine transport trailers impose high dynamic loads on freshly laid tracks. Secugrid® geogrids and Combigrid® composite products are designed to support safe, efficient construction for each site condition, from routine reinforcement to integrated filtration on deep peat.
Practical advantages:
On many wind farm sites, bearing capacity alone is not the only engineering challenge. When fine particles migrate from soft peat or a clay subgrade into the granular base course, the base course becomes contaminated, drainage is impaired and track performance deteriorates. On these sites a separation and filtration layer is essential for long-term performance.
Key principle: Reinforcement improves load-bearing capacity. Separation and filtration protect the base course over the long term.
The choice of geosynthetic system depends on subgrade conditions, traffic loading and the need for filtration. The decision table below provides a direct comparison of five site scenarios typical of onshore wind farm construction. In addition, you can find a digital, question-based SolutionFinder and several calculation tools in the Naue Portal.
| Criterion | Subgrade CBR | Filtration required? | Recommended product | Typical wind farm use |
|---|---|---|---|---|
| Stable subgrade, reinforcement only | > 3% | No | Secugrid® (single layer) | Good ground access tracks, substation roads |
| Weak subgrade, load spread needed | 1% to 3% | No/optional | Secugrid® 30/30 Q1 or 40/40 R6 | Upland access tracks, turbine road sections |
| Soft/peaty subgrade, separation critical | 0.5% to 1.5% | Yes | Combigrid® 40/40 Q1 GRK 4 C (geogrid + filter geotextile) | Peat-crossing sections, crane hardstandings on soft ground |
| Very soft subgrade, multi-layer system | < 0.5% | Yes | Combigrid® base layer + Secugrid® upper layer | Deep peat crossings, extremely soft ground |
| Slope erosion on embankments | N/A | N/A | Secumat® erosion control mat + Secutex® filter | Cut/fill slopes at turbine base and access road edges |
Bearing capacity on any subgrade
Secugrid® and Combigrid® allow engineering teams to specify access tracks that meet required bearing capacity targets on CBR values as low as 0.5%. Geosynthetic reinforcement can significantly reduce the base course depth required, cutting fill material and the need for deep aggregate excavation on peaty highland terrain.
Fast installation, tight programmes
Combigrid® is supplied in 4.75 m wide, 100 m long rolls. Rolls are simply unrolled, overlapped and covered with base course aggregate in a single pass. Reduced aggregate use means fewer deliveries and a lower material footprint for wind farm infrastructure.
Long-term track life
Either a geotextile separation/filtration layer or integrated filtration in Combigrid® prevents fines migration from peat subgrades into the granular layer. This extends track service life and reduces maintenance and reinstatement costs over the wind farm operational lifetime (typically 25 years).
Geosynthetic reinforcement for wind farm access roads means the installation of geogrids between the subgrade and the granular base course. The geogrid mobilises interlock and friction with the aggregate to distribute axle loads and increase the bearing capacity of the road structure. On soft or peaty upland sites, this approach replaces or significantly reduces the need for deep aggregate excavation.
Use Secugrid® where the subgrade CBR is above 3% and no filtration requirement exists. Use Combigrid® where the CBR is below 3%, particularly on peaty or soft cohesive soils, and where fine particle migration into the base course is a risk. Combigrid® integrates the Secugrid® geogrid with a Secutex® nonwoven geotextile in a single product, removing the need for a separate filtration layer.
Primary design standards include BS 8006-1 (reinforced fills), EBGEO (German geosynthetics guidelines) and BRE BR 470 (working platforms for tracked plant). BS 8004 applies to foundation ground conditions. Naue engineering teams provide preliminary designs based on site-specific CBR values, traffic loading and project standards. In addition, there are a digital, question-based SolutionFinder and several calculation tools available free of charge.
Combigrid® is supplied in 4.75 m wide, 100 m long rolls. Rolls are placed directly on the prepared subgrade, unrolled in the direction of traffic and overlapped at joints. No specialist equipment is required. The base course aggregate is placed and compacted immediately on top. For peat subgrades, Naue recommends a minimum 300 mm working layer of aggregate before compaction plant accesses the geogrid layer.
Secugrid® and Combigrid® are CE-marked products manufactured under ISO 9001 quality management. Design methods comply with EBGEO, BS 8006-1 and BRE BR 470. Naue products have been specified by leading wind farm consultants and used on projects by major contractors. Contact us for project-specific evaluation and advice.
Yes. Naue geosynthetics have been deployed on wind farm projects in the UK, Ireland and across Europe, including North Kyle Wind Farm (Scotland, 49 turbines). Project reportings are available in the case studies section.
On very soft peat with CBR below 0.5%, a multi-layer geosynthetic system is recommended: Combigrid® as the primary base layer, providing reinforcement and filtration simultaneously, with a secondary Secugrid® layer above where additional load-spreading is required. A working platform of at least 300 mm aggregate must be placed before tracked compaction plant accesses the system. Naue engineering teams provide project-specific design for these conditions using EBGEO Chapter 6 and BRE BR 470 methods.
Secumat® three-dimensional erosion control mats are installed directly on the graded slope surface after earthworks are complete. The mat is pinned at the crest and unrolled down the slope, with overlaps at joints. Topsoil and seed are applied over the mat or hydroseeded through the mat structure. The three-dimensional fibre network prevents surface erosion under rainfall, promotes root development and stabilises the slope vegetation over the long term. Secumat® is UV-stabilised and designed for permanent slope protection at wind farm sites.
Geosynthetic systems for wind farm access infrastructure are dimensioned on the basis of recognised engineering standards. Naue's design software as well as the engineering support team help you identify the optimum solution for your site conditions quickly, reliably and in compliance with applicable standards.
Naue Secugrid® geogrid stabilises and reinforces roads, embankments, working platforms, slopes and walls.
Naue Combigrid® is a geogrid with integrated nonwoven geotextile that combines stabilisation, reinforcement, separation and filtration in a single installation step.
Naue Secutex® is a mechanically bonded nonwoven geotextile for separation, filtration and protection in roads, railways and hydraulic engineering projects.
Naue Secumat® is an erosion control mat for the protection of slopes, channels and embankments.
