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Solar farm with rows of panels built on a soft ground that is stabilised with Naue geogrid solutions.

Stability for solar farms

Geosynthetics for soft ground

The stabilisation of ground for solar energy projects involves the engineering of load-bearing access tracks, crane pads and working platforms on weak or variable subgrades. Soft ground, peat and low-bearing soils cause rutting and structural failure. Naue Secugrid® and Combigrid® solve this challenge through subgrade reinforcement and integrated filtration.

At a glance

  • Construction and stabilisation of access tracks, crane pads, working platforms and internal haul roads for solar farm construction on soft subgrades
  • Secugrid® geogrid, Combigrid® geocomposite, Secutex® geotextile, Secumat® erosion control system
  • BS 8006-1, EBGEO, BS EN ISO 10319, BS EN 13249/13251 (project-specific standards apply)
  • Solar farms, photovoltaic arrays, on-site access tracks, cable routes and substation compounds

Stabilise ground for solar farms: challenges, solutions and results

Challenges

  • Soft, peaty or waterlogged subgrade (CBR < 2%)
  • Rutting under heavy plant and delivery vehicles
  • Access track failure during the construction phase
  • Erosion on slopes around panel arrays
  • Tight construction programmes and cost pressure

Solution

  • Secugrid® for subgrade stabilisation and load distribution
  • Combigrid®: reinforcement + stabilisation + separation + filtration in one layer
  • Secutex® to protect aggregate from long-term fines migration
  • Secumat® erosion control mat for vegetated slope stabilisation

Result

  • Immediately load-bearing surface on difficult subgrades: fewer ruts and longer service life for access tracks
  • Reduced aggregate depth required; savings compared to conventional ground exchange or thick fill
  • Long-term slope stability through erosion control
  • System solution from a single supplier

Typical applications in solar energy projects

Naue geosynthetics are used wherever load-bearing capacity, long-term durability and economic performance are critical on solar farm construction sites.

  • Base course stabilisation

    Access tracks

    Stabilise weak peat or clay subgrades to carry construction plant and long-term maintenance vehicles

  • Solar energy working platforms

    Crane pads and working platforms

    Load-bearing platforms for module mounting, inverter installation and maintenance access

  • Reinforced foundation

    Substation and cable routes

    Stable subbases for cable trenches, substation and access compounds

  • Erosion control on technical structures

    Slope erosion control

    Erosion protection and revegetation on steep slopes below photovoltaic arrays

Truck driving on a solar farm access road on soft subsoil that is stabilised with Naue Combigrid® geocomposite.
Truck driving on a solar farm access road on soft subsoil that is stabilised with Naue Combigrid® geocomposite.

Robust in installation, reliable in performance

Solar farm sites are typically remote and located on soft, waterlogged or peaty ground. Secugrid® geogrids and Combigrid® composite products are designed for demanding site conditions. They perform reliably on challenging subgrades and tight build programmes without specialist plant or extended operative training. Geogrid solutions deliver stability across the full construction cycle from first access to long-term maintenance.

Practical benefits:

  • Stable aggregate layer structure under repeated heavy plant loading
  • Reduced risk of rutting and deformation during construction and maintenance phases
  • Available in 100 m x 4.75 m rolls for efficient remote site logistics
  • System solutions covering stabilisation and, where required, separation and filtration

Solar energy ground engineering: frequently asked questions

Ground stabilisation for solar energy projects involves the engineering of load-bearing access tracks, crane pads and working platforms on weak subgrades. Soft ground, peat and fine-grained soils cause rutting and structural failure under heavy plant. Secugrid® and Combigrid® geogrids reinforce the subgrade to deliver stable, durable surfaces for construction and long-term maintenance traffic.

Use Secugrid® when the focus is on bearing capacity and load distribution on cohesive or granular subgrades (CBR ≥ 2%). Use Combigrid® when fines migration is a risk, e.g. on soft, peaty or fine-grained subgrades (CBR < 2%). Combigrid® integrates a Secutex® filtration layer in a single product, simplifying installation on remote sites and reducing the number of construction interfaces.

Naue software tools help to select the optimum Naue solution for your project. For project-specific advice you can also contact the Naue engineering team.

Design follows recognised standards including BS 8006-1 (reinforced fills and slopes), EBGEO (German geosynthetic design guidelines) and BS EN ISO 10319 (geotextile tensile testing). CE marking is covered under BS EN 13249 and EN 13251. Project-specific requirements from the site engineer or developer also apply. Naue provides standards-compliant design support.

Geogrid reinforcement can reduce the required aggregate depth compared with an unreinforced design on soft subgrades. This directly reduces material and transport costs. In many cases, ground exchange is avoided entirely, reducing construction duration and site disturbance.

Combigrid® is supplied in 100 m x 4.75 m rolls and installed directly onto the prepared subgrade. Rolls are overlapped at joints by a minimum of 300 mm. Aggregate is placed immediately after installation to anchor the product. No specialist plant is required. The combined geogrid and geotextile in one product significantly reduces handling time on remote solar farm sites.

Yes. Multiple Secugrid® and Combigrid® grades carry CE marking under EN 13251. Secutex® products are certified under EN 13252 and EN 13253. Documentation is provided in European Technical Assessments and Declarations of Performance. Contact Naue for project-specific certification documentation.

Yes. Secumat® erosion control mats stabilise vegetated slopes around photovoltaic arrays and drainage channels. The three-dimensional mat structure promotes root growth and prevents surface erosion under rainfall. Secumat® 401 G4 is UV-stabilised for long-term outdoor performance.

Secugrid® and Combigrid® are designed with high stiffness at low elongation (approx. 18 kN/m at 2% strain) to deliver effective load transfer under repeated cyclic loading. The geogrid is made of stretched, monolithic flat bars that are welded at the junctions, giving high junction strength and controlled long-term creep behaviour.

Secumat® 401 G4 is installed directly over the compacted slope surface after earthworks are complete. On steep slopes (gradient > 1:2) it may be combined with Secutex® geotextile as an interface protection layer. Secugrid® can be incorporated as a basal reinforcement layer at the slope toe where surcharge loads from panel structures act on the slope face. Naue provides project-specific slope design support (personally and digitally in the Naue Portal) using standards-compliant methods (BS 8006-1, EBGEO).

Project-specific geosynthetic design for solar farm sites

The design of geogrid systems for solar farm access tracks and crane pads follows recognised standards including BS 8006-1, EBGEO and project-specific ground investigation data. Naue's design tool supports you in identifying the optimum system for your project quickly and in accordance with the relevant standard and with full traceability.

  • BS 8006-1: Code of practice for strengthened/reinforced soils and fills
  • EBGEO: German geosynthetic design guidelines (earthworks and geotechnics)
  • BS EN ISO 10319: Geotextile wide-width tensile test
  • ZTV E-StB: Technical specifications for earthworks in road construction
  • BS EN 13249/13251: CE marking for geogrids and geotextiles in earthworks applications
Stabilizer outriggers of a crane during solar park construction extended onto support pads stabilised with Naue Secugrid® geogrids.
Stabilizer outriggers of a crane during solar park construction extended onto support pads stabilised with Naue Secugrid® geogrids.

How geosynthetics work on solar farm sites

  1. Stable base course through Secugrid® or Combigrid® geogrid reinforcement
  2. Reduced rutting through optimised load distribution under heavy plant
  3. Integrated separation and filtration function (Combigrid®)
  4. Reduced aggregate depth compared to conventional unreinforced design
  5. Erosion-controlled slopes through Secumat® ground cover

Geotechnical software

Naue Portal - the free digital platform for geotechnical engineers.

Naue Portal: your all-in-one free geotechnical software solution for planning and cost estimation

  • One platform – multiple solutions: access a wide range of geotechnical design tools in a single portal.
  • User-friendly and accessible: available anytime, anywhere via desktop or mobile.
  • Optimised cost and material usage: reduce construction costs while ensuring long-term project stability.
  • Compliant with industry standards: aligns with AASHTO, and other engineering guidelines.