Reinforced Soil wall (RS): the modern variants explained.
Reinforced Soil wall is the generic English-language term for the broad category of soil-reinforcement retaining walls. While Reinforced Earth refers specifically to the Henri Vidal steel-strip system, Reinforced Soil covers all the descendants: geogrid-reinforced, geotextile-reinforced, welded-wire-mesh-reinforced, polymeric-strip variants, and the anchored systems. Each variant has its own design code path, its own pullout mechanism, its own durability story. This guide walks through them all so you can pick the right variant for the project, write the right tender spec, and understand what the contractor is actually building.
The taxonomy of Reinforced Soil walls
"Reinforced Soil" is an umbrella term covering all soil-reinforcement retaining systems regardless of reinforcement type. Six families are in active use in 2026:
| Variant | Reinforcement | Typical backfill | Design code |
|---|---|---|---|
| Reinforced Earth (steel strip) | Galvanised flat or ribbed steel strip | Granular sand or gravel, phi greater than 36 deg | BS 8006, FHWA NHI-10-024 |
| Welded steel wire mesh | Welded grid of steel wires | Granular, phi greater than 35 deg | BS 8006, FHWA NHI-10-024 |
| Geogrid (HDPE) | Polymer grid, punched-and-drawn | Granular or selected cohesive | BS 8006, FHWA NHI-10-024, GRI |
| Geogrid (PET woven) | Polyester woven grid coated with polymer | Granular or selected cohesive | BS 8006, FHWA NHI-10-024, GRI |
| Polymeric strip | PET fibre core in HDPE sheath | Granular, phi greater than 34 deg | BS 8006, FHWA, manufacturer technical guides |
| Geotextile (wrapped face) | Nonwoven geotextile, wrap-around | Granular, temporary or low-consequence | BS 8006, FHWA, temporary works codes |
| Anchored MSE (AnchorSOL) | Carbon steel deformed bar with deadman block | Crusher run, phi greater than 34 deg | BS 8006, FHWA, AnchorSOL technical specification |
Geogrid-reinforced soil walls
Polymeric geogrids appeared in the late 1970s and became the most widely-used Reinforced Soil reinforcement after steel strips. Two principal types:
HDPE punched-and-drawn geogrids
High-density polyethylene sheet punched to a regular pattern then drawn (stretched) in one or two directions to orient the polymer chains and develop tensile strength. Junctions are integral (not welded or knitted), giving uniform strength at the rib-to-junction interface. Typical short-term tensile strength 30 to 150 kN/m for uniaxial grades.
Durability: HDPE is resistant to most chemicals and biological attack. Creep is the principal long-term concern; the design code requires a creep-reduction factor (typically 0.4 to 0.6) applied to short-term strength to get the long-term design strength over a 100-year design life.
PET woven geogrids
Polyester fibre yarns woven into a grid, coated with PVC or HDPE for UV and abrasion protection. Higher initial stiffness than HDPE geogrids but more creep-sensitive. Typical short-term tensile strength 50 to 300 kN/m.
Durability: PET is sensitive to high pH (alkaline conditions) and to elevated temperatures. Design codes require pH and temperature reduction factors in addition to creep.
Geogrid wall facings
Geogrid-reinforced walls use a variety of facings:
- Modular block facing (segmental retaining wall, SRW): small dry-stack concrete blocks, popular for residential and light-commercial walls
- Precast concrete panel facing: similar to Reinforced Earth panels but with geogrid connection detailing
- Wrapped-face soft facing: the geogrid itself wraps around the face of each lift, used for temporary works and low-consequence walls
- Welded wire facing: galvanised wire mesh, with vegetation behind for "green wall" architectural effects
Welded wire mesh reinforced walls
Welded steel wire grid embedded in granular fill behind a facing. The grid has high interaction coefficient with granular fill (alpha typically 1.0 to 1.6) because transverse bars produce passive bearing resistance against the soil as the grid is pulled. Suitable for granular fill at phi 35 degrees and above.
Common in North American practice, less in Malaysia, but specified on some federal road projects where the system fits the design programme.
Polymeric strip reinforced walls
A composite reinforcement: a high-strength PET (polyester) fibre core enclosed in an extruded HDPE sheath. Combines the high strength of PET with the durability of HDPE. Typical short-term tensile strength 50 to 200 kN per strip.
Used in tight-tolerance modern MSE walls with precast concrete facing. Marketed under various brand names. Design follows the same friction-based pullout approach as steel-strip Reinforced Earth.
Geotextile wrapped-face walls
Nonwoven geotextile used both as reinforcement and as the facing (wrapped at each lift around the front face). Used for temporary works, low-consequence walls, and sites where a vegetated face is acceptable. Typically not suitable for permanent infrastructure walls due to UV degradation and limited tensile capacity.
How to pick the right variant
The selection question reduces to four factors:
1. Backfill availability and cost
Premium granular fill is expensive in Malaysia (RM 80 to 140 per m^3). Crusher run from local quarries is half the cost. If premium granular is committed in the budget, friction-based systems including Reinforced Earth and geogrid work fine. If crusher run is the practical source, anchored MSE (AnchorSOL) is the cost-efficient default.
2. Design life and durability
For 100-year and 120-year design lives common on infrastructure, steel-based systems (Reinforced Earth, anchored MSE) outperform polymeric systems on durability. Polymeric systems require larger creep-reduction factors over long design life, eating into their initial cost advantage.
3. Reinforcement length and footprint
Friction-based systems need reinforcement length L greater than 0.7 H. On tight sites with limited reach behind the wall face, anchored systems with shorter effective length offer footprint advantage.
4. Aesthetic and operational requirements
Precast concrete facing (Reinforced Earth, AnchorSOL) wins for architectural specifications. Modular block facing suits residential and amenity walls. Wrapped-face suits temporary or vegetated.
See Wall Selection Decision Tree for a comprehensive matrix.