A Berlin wall (also called soldier pile wall or soldier beam and lagging wall) is a temporary earth retention system consisting of steel H-profiles driven or drilled into the ground, with horizontal timber planks or steel plates inserted between them. This construction supports the walls of an excavation pit during digging work, preventing the surrounding soil from collapsing inward.
The name refers to Berlin, Germany, where this technique was developed in the early 20th century for the construction of the city’s underground railway system. The method proved so effective and cost-efficient that it was quickly adopted worldwide as a standard solution for temporary excavation support.
Applications
The Berlin wall system is used in a variety of construction scenarios:
- Urban excavation pits — When digging basements, underground car parks, or foundations in built-up areas where space is limited and neighbouring structures must be protected.
- Utility and sewer works — As support for deep trenches required for laying cables, pipes, and drainage systems.
- Temporary earth retention — When a permanent basement wall or retaining wall has not yet been constructed, the Berlin wall holds the soil in place during the interim period.
- Underground railway and tunnel construction — The original application, still widely used in major infrastructure projects today.
How is a Berlin wall constructed?
- Install H-profiles — Steel H-beams (called “soldiers”) are driven or drilled into the ground at regular intervals, typically 1.5 to 3 metres apart.
- Excavate in stages — The soil is removed layer by layer, working downward in controlled phases.
- Insert lagging — After each excavation phase, timber planks or steel plates are slid horizontally between the H-profiles to resist the lateral earth pressure.
- Anchor if needed — At greater depths, ground anchors or struts (bracing) are added for additional stability.
The main advantage of a Berlin wall is that it is relatively fast and inexpensive to build compared to alternatives such as sheet pile walls or diaphragm walls. A disadvantage is that the construction is not watertight, making it less suitable in situations with a high groundwater table unless supplementary dewatering measures are taken.
Related terms
- Sheet pile wall
- Earth retention
- Shoring
- Ground anchor
- Diaphragm wall
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