Retaining walls are constructed in various ways depending on the type and application. One common method for constructing a specific type, known as reinforced soil retaining walls, involves reinforcing the soil itself to create a stable structure.
Constructing Reinforced Soil Retaining Walls
Reinforced soil retaining walls, also sometimes referred to as mechanically stabilised earth walls, are constructed using a technique that strengthens the soil fill behind the wall face.
The core principle of this construction method is the use of layers of geogrid. These geogrid layers are placed horizontally within the soil fill at specific intervals as the wall is built upwards.
The geogrid interacts with the soil through friction, effectively reinforcing the soil into a stabilised mass. This composite structure of soil and reinforcement acts as the main structural element of the retaining wall.
The construction typically proceeds in layers:
- Foundation Preparation: The base of the wall is prepared and leveled.
- Facing Element Placement: The facing units (like concrete blocks, modular panels, or wire mesh) that form the visible face of the wall are placed on the foundation.
- Soil Placement: Soil fill is placed behind the facing unit.
- Compaction: The soil layer is compacted to achieve the required density.
- Geogrid Installation: A layer of geogrid is laid horizontally on top of the compacted soil, extending back into the fill area.
- Repeat: Steps 2-5 are repeated, adding alternating layers of facing, soil, and geogrid until the desired height is reached.
Benefits of Reinforced Soil Construction
This method provides significant structural advantages:
- It increases the bearing capacity of the retaining structure, allowing it to support greater loads from the retained soil and any structures or loads above it.
- It improves the wall's resistance to differential settlement, helping the structure remain stable even if there are variations in the underlying ground conditions.
By integrating the reinforcement directly into the soil mass, reinforced soil walls offer a durable and effective solution for earth retention.
