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Dump truck unloading gravel onto a Naue Secugrid® geogrid base during rural road construction beside excavators and earthmovers.

Naue UnpavedRoad – modified GH

Smarter temporary access and haul roads

Naue UnpavedRoad – modified GH is a free online calculator in the Naue Portal DesignSuite for designing unpaved roads: temporary access roads, haul roads and working areas. It determines the required thickness of the unbound base course project-specifically, using the proven modified Giroud & Han method (2004), taking account of the subgrade bearing capacity, the expected traffic loading and the permissible surface deformation (rut depth). By building in the measured performance of Secugrid® geogrids and Combigrid® geocomposites, the tool shows how much the unbound base course can be reduced, cutting material, cost, and construction time while keeping the road stable and durable, even over soft subsoils.

At a glance

  • What it is: a free online calculator in the Naue Portal DesignSuite (login required)
  • What it does: assists with the design of the unbound base course of unpaved roads to the modified Giroud & Han method
  • Best for: temporary access roads, haul roads and working areas - including sites over soft subsoils
  • Key inputs: vehicle type; axle load F (kN); wheel width D (cm); permissible rut depth (mm); number of passes N; lane-tracking effect; subgrade (CBR or Ev2/modulus); base-course material; Secugrid®/Combigrid® reinforcement
  • Key outputs: required unbound base-course thickness with and without geogrid; thickness reduction; cost savings versus conventional; downloadable report
  • Method: Modified Giroud & Han (2004), with wheel-wandering (lane-tracking) simulation

From traffic and subgrade data to a leaner base course: how UnpavedRoad delivers

Challenges

  • Building stable temporary roads over weak or soft subsoils
  • Thick base courses drive material, haulage cost and time
  • Proving the savings from geogrid stabilisation

Naue solution

  • A modified Giroud & Han calculator that includes the stabilisation, reinforcement and separation effect of Secugrid® and Combigrid® geogrid solutions

Results

  • The required base-course thickness for your rut and traffic limits
  • A reduced base course with geogrid, at equal performance
  • Quantified cost savings versus conventional, with a downloadable report

Where UnpavedRoad – modified GH helps: applications covered

Naue UnpavedRoad – modified GH is used wherever a stable, cost-effective unpaved road or working area is needed, especially on weak subsoils where geogrid stabilisation delivers the greatest savings.

  • Temporary access roads: stable, cost-effective access for construction and industrial sites.
  • Haul roads: durable routes for heavy construction and site traffic.
  • Working areas and platforms: load-bearing surfaces for plant, laydown and staging areas.
  • Soft subsoil sites: geogrid stabilisation where subgrade bearing capacity is low.
  • Wind energy access: stable platforms and access roads for onshore wind projects.

How UnpavedRoad – modified GH works: input, geogrid benefit and savings

A guided form collects the road, traffic and ground data and returns the required base-course thickness. It incorporates the geogrid benefit and the cost saving made explicit, and the option to save the calculation to a project.

Visual in the Naue UnpavedRoad calculator showing an unpaved road and a twin wheel axle operating on it with labeled geometric parameters.
Visual in the Naue UnpavedRoad calculator showing an unpaved road and a twin wheel axle operating on it with labeled geometric parameters.

Enter your road, traffic and ground data

Define the load, the performance requirement and the ground. UnpavedRoad then determines the required unbound base-course thickness so the road meets your rut-depth and traffic limits.

Practical advantages:

  • Load input: vehicle type, axle load (kN) and wheel width (cm); tyre contact pressure is derived automatically
  • Requirements: permissible rut depth (mm) and number of axle passes, with an optional lane-tracking (wheel-wandering) effect
  • Subgrade defined by CBR or Ev2 / elasticity modulus, with a selectable subgrade type
  • Base-course material and its stiffness, plus selection of the Secugrid®/Combigrid® reinforcement
  • Mobile and desktop access for on-the-go planning

UnpavedRoad – modified GH: method, standards and engineering support

Method / frameworkScope
Modified Giroud & Han (2004)Design of the unbound base-course thickness for unpaved roads
Rut-depth criterionPermissible surface deformation of the base course governs the design
Geosynthetic stabilisationStabilisation, reinforcement and separation effect of Secugrid® and Combigrid® built into the design
Naue EDDProject-specific review, verification and design support
UnpavedRoad is based on the modified Giroud & Han method for unpaved roads, combined with the measured performance of Naue geogrids. Where a project needs individual review, the Naue Engineering and Design Department (EDD) supports planners and contractors with project-specific design.

The UnpavedRoad advantage: build temporary roads smarter

Naue UnpavedRoad – modified GH lets engineers build temporary roads cleverly, save money and improve efficiency, and create robust, stable solutions even on soft subsoils. By optimising the unbound base-course thickness with Secugrid® and Combigrid®, it reduces material and construction costs and time, and quantifies the saving against conventional designs - all from a fast, intuitive tool accessible on web and desktop, backed by Naue's engineering support.

Naue UnpavedRoad – modified GH: frequently asked questions

Naue UnpavedRoad – modified GH is a free online calculator in the Naue Portal DesignSuite. It helps to design the unbound base course of unpaved roads like temporary access roads, haul roads and working areas, using the modified Giroud & Han method and the performance of Secugrid® geogrids and Combigrid® geocomposites.

It is based on the proven Giroud & Han approach (2004), refined ('modified') to incorporate the advanced performance properties of Naue Secugrid® geogrids and Combigrid® geocomposites for a more efficient and reliable design.

For temporary and unpaved roads: construction and industrial access roads, haul roads, working platforms and staging areas - particularly where the subgrade is weak or soft.

The load (vehicle type, axle load and wheel width), the requirements (permissible rut depth and number of passes, with an optional lane-tracking effect), the subgrade (type and CBR or Ev2/modulus), the base-course material, and the Secugrid®/Combigrid® reinforcement.

They provide a combined stabilisation, reinforcement, separation, and filtration effect. Based on verified product performance, the tool reduces the required unbound base-course thickness at equal performance, cutting aggregate use and cost.

Yes. An optional wheel-wandering (lane-tracking) simulation spreads wheel loads laterally across the road width, reducing stress on weak subsoils. Vehicle configurations can be converted into ESALs using the Naue AxleLoad tool.

It calculates the total saving compared with a conventional solution without geosynthetics, produces a downloadable report, and lets you save the calculation to a project in the Naue Portal.

It is free within the Naue Portal and requires a portal login, with mobile and desktop access. You can register here. The software tools are aimed at design engineers, planners, contractors and project owners.