Soft ground construction describes the process of building embankments, roads and structures on weak or compressible subgrade, including peat, soft clay and saturated soils. Differential settlement and bearing capacity failure are the primary risks. Secugrid® and Combigrid® geosynthetics from Naue distribute loads, control settlement and maintain structural integrity, reliably and in compliance with international standards.
Geosynthetic reinforcement from Naue is used wherever structures must be built on weak, compressible or saturated ground.
Constructing stable road embankments over saturated peat or bog with basal geosynthetic reinforcement.
Creating safe, load-bearing working platforms for piling rigs and heavy construction equipment on soft clay.
Stabilising infrastructure foundations on soft clay or similar compressible subgrade.
Designing reinforced granular platforms over pile heads to transfer and distribute loads on weak ground.
Enabling construction across wetlands, bogs and saturated soils without excessive disturbance of natural habitats.
Soft ground construction imposes severe demands on geosynthetics during and after installation. Secugrid® and Combigrid® are engineered for high installation survivability - even on saturated, peat or very soft subgrade. Their flat monolithic bars resist dynamic loads and mechanical damage from aggregate compaction.
Practical advantages:
On soft ground, fine particles from the subgrade can migrate upward into the granular fill layer. This process - known as subgrade contamination - clogs the aggregate, reduces drainage capacity and progressively destroys bearing capacity. Secutex® nonwoven geotextiles and the integrated geogrid in Combigrid® prevent this migration.
Key principle: Reinforcement improves bearing capacity. Separation and filtration protect long-term performance.
Technical benefit: Components can be independently specified and replaced.
Technical benefit: Fewer layers, faster installation, no risk of component misalignment.
The correct product choice depends on subgrade conditions, loading requirements and the need for separation and filtration. The following decision guide covers six criteria - select the column matching your project conditions.
| Criterion | Secugrid® only | Secugrid® + Secutex® | Combigrid® |
|---|---|---|---|
| Subgrade CBR value | CBR > 5 % | CBR 3–5 % | CBR < 3 % |
| Separation / filtration need | Not required | Required - separate layer acceptable | Required - single layer preferred |
| Loading class | Moderate - static or light dynamic | Moderate to heavy — dynamic loads | Heavy - repeated dynamic loading on very soft ground |
| Installation speed | Standard | More complex - two layers to align | Fastest - single composite layer |
| Peat or bog subgrade | Not recommended | Possible with care | Recommended |
| Working platforms (piling rigs) | Only for firm subgrade CBR > 5 % | Suitable with separate filter | Recommended - CBR < 3 % (according to Naue technical documentation) |
Fast installation - avoid costly ground replacement
Geosynthetic reinforcement eliminates or significantly reduces the need for full subgrade excavation and replacement. Combigrid® reduces aggregate depth requirements. Wide rolls are unrolled directly onto soft subgrade and covered rapidly.
Settlement control for long-term structural performance
Secugrid® basal reinforcement distributes loads more evenly over the soft subgrade. The Bangkok Srinakarin Road project (329,000m2 of Secugrid®) demonstrates reduced stress concentration and controlled differential settlement.
Verified compliance with international standards
Design in accordance with EBGEO, BS 8006-1, DIN 4084 / Eurocode 7 and CUR 226. Load transfer platforms designed according to EBGEO and BS 8006-1. FEM analysis (PLAXIS) confirms embankment stability on soft subsoils.
Soft ground construction describes the design and building of roads, embankments and structures on weak, compressible or saturated subgrade - such as peat, soft clay or waterlogged soils. It is required when the subgrade cannot support structural loads without reinforcement, and where differential settlement must be controlled.
Secugrid® is suitable for subgrade with CBR values greater than approximately 3%, where reinforcement alone is required. Combigrid® is recommended for CBR values below 3%, as it combines reinforcement, separation and filtration in a single layer - reducing installation complexity and protecting long-term bearing capacity.
Soft ground reinforcement design follows EBGEO (Germany), BS 8006-1 (UK), DIN 4084 / Eurocode 7, and CUR 226 (Netherlands). For load transfer platforms over piles, EBGEO and BS 8006-1 are the primary references. FEM analysis (PLAXIS) is used for complex embankment stability assessments on very soft subsoils.
Geosynthetic reinforcement can eliminate or substantially reduce excavation and aggregate replacement costs. In documented projects, aggregate depth reductions of 30–50% compared with unreinforced designs have been achieved. Faster installation and reduced transport requirements further improve project economics.
Combigrid® or Secugrid® rolls are unrolled directly onto the soft subgrade surface without heavy machinery. Combigrid® in 4.75 m wide rolls covers full road widths with minimal joints. The reinforcement layer is covered immediately with granular fill - avoiding excessive trafficking of the soft surface. Overlaps of at least 300 mm are maintained.
Yes. Solutions designed in accordance with EBGEO (Germany), BS 8006-1 (UK) and Eurocode 7 are accepted across European jurisdictions. In North America, geosynthetic base course reinforcement on soft ground is designed in accordance with AASHTO, FHWA guidelines and relevant state DOT standards. Naue's engineering team supports project-specific design verification.
Yes. Naue has supplied Secugrid® and Combigrid® to soft ground projects worldwide - from road embankments on soft clay (329,000 m2 of Secugrid®) to bog reinforcement in Alaska, peat highway rehabilitation in Canada and wetland pathway construction. Reference projects are available in our case studies.
A load transfer platform (LTP) is a reinforced granular layer placed over a pile grid to transfer embankment loads from soft ground to the pile heads. Secugrid® provides the tensile reinforcement element within the platform, designed to EBGEO and BS 8006-1. This allows smaller pile spacings and eliminates the need for a rigid pile cap slab in many applications.
In many cases, geosynthetic reinforcement combined with an optimised fill design can replace or substantially reduce the need for deep foundations such as piling or stone columns. Combigrid® on CBR < 3 % subgrade has demonstrated equivalent bearing capacity at a fraction of the cost. Project-specific FEM analysis confirms whether geosynthetic reinforcement alone is sufficient.
The design of geosynthetic reinforcement for soft ground follows recognised international standards. Naue's engineering team provides project-specific analysis using EBGEO, BS 8006-1, Eurocode 7 and FEM methods.
The following system benefits come directly from how the Naue products work within the layer structure:
Naue Combigrid® is a geogrid with integrated nonwoven geotextile that combines stabilisation, reinforcement, separation and filtration in a single installation step.
Naue Secugrid® geogrid stabilises and reinforces roads, embankments, working platforms, slopes and walls.
Naue Secutex® is a mechanically bonded nonwoven geotextile for separation, filtration and protection in roads, railways and hydraulic engineering projects.
