In New Zealand, there are several types of retaining walls commonly used for various purposes. Here are some of the different types:
- Gravity Retaining Walls: Gravity retaining walls rely on their weight and mass to resist the pressure exerted by the soil behind them. They are typically constructed using heavy materials like concrete or stone blocks. Gravity walls are suitable for lower height applications and can have a decorative appearance.
- Cantilever Retaining Walls: Cantilever retaining walls are designed with a horizontal base or footing and a vertical wall section that leans back into the retained soil. They utilize the principle of leverage to counteract soil pressure. Cantilever walls are commonly made of reinforced concrete and can be more suitable for taller walls compared to gravity walls.
- Anchored Retaining Walls: Anchored retaining walls provide additional stability by incorporating anchors or tiebacks into the wall structure. These anchors are typically steel rods or cables that extend into the soil behind the wall and are anchored to a stable location, such as a concrete deadman or a rock mass. Anchored walls are used when high loads or challenging soil conditions are present.
- Gabion Walls: Gabion walls are constructed using wire mesh baskets filled with rocks or other suitable materials. The baskets are stacked to create a wall structure that retains the soil. Gabion walls offer good drainage and are often used in areas where a more natural and aesthetically pleasing appearance is desired.
- Retaining Wall Blocks: Retaining wall blocks are precast concrete blocks specifically designed for retaining wall construction. These blocks interlock with each other to create a stable wall system. They come in various shapes, sizes, and textures, allowing for versatile design options.
- Timber Retaining Walls: Timber retaining walls are constructed using pressure-treated timber boards or sleepers. They are commonly used for smaller retaining walls and have a more rustic appearance. Proper drainage and treatment are essential to ensure the longevity and durability of timber retaining walls.
It’s important to consider factors such as the height of the wall, soil conditions, aesthetic preferences, and budget when selecting the most suitable type of retaining wall for a specific project in New Zealand. Consulting with a professional engineer or retaining wall contractor is recommended to ensure compliance with local regulations and to design a wall that meets the specific requirements of the site.