Entire implementation? With a single partner
We combine our expertise to create a customized, comprehensive solution for you.
Foundations
The start of a solid foundation
When the ground conditions are unpredictable and structures have increasingly demanding requirements, we work with you to find the best way to ensure stability. We look beyond standard solutions to determine what a project truly needs.
Applications
No matter what foundation challenge you face, we can provide a smart solution for:
- Infrastructure such as bridges, roads and railways, stations, and sewer systems
- Project development
- Industrial construction and industrial flooring
- Renovation of quay walls, historic landmarks, and bridges
- Unique projects without a ready-made solution
Retaining walls
In CSM (Cutter Soil Mixing), cutters mix the subsoil with grout to form a solid, waterproof retaining wall. The wall thickness varies from 50 cm to 1 meter. The depth can reach up to 35 meters.
In contrast, TSM (Tubular Soil Mixing) uses a single drill pipe with a tip for this purpose. Variations include Twin Soil Mixing and Triple Soil Mixing, in which 2 or 3 piles are driven simultaneously.
We offer two types of secant piles:
- double rotation (tubular)
- Kelly piles (drilled)
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The retaining wall is constructed by alternating overlapping primary and secondary concrete piles. These secant piles are cast in place and have a diameter ranging from 400 mm to 1,000 mm, extending to a depth of 24 meters.
The secant walls can also be constructed as Kelly piles and can range in diameter from 600 mm to 1,400 mm and in depth up to 35 meters.
In VHP (Very High Pressure) grouting or jet grouting, retaining walls are constructed using grout piles. These have diameters ranging from 500 mm to 1,500 mm and depths of up to 30 to 40 meters. VHP piles are created by injecting grout into the ground under very high pressure while the drill rods rotate. Traditionally, VHP is most commonly used in urban areas where there are obstacles in the subsoil and/or in spaces where limited headroom makes it difficult to work with larger foundation machines.
Shored trenches are hand-dug, narrow shafts that are typically 1 meter to 1.2 meters wide. The manual excavation is done in 400-mm increments, after which the walls are shored with precast concrete panels (or wood) that slot into place. Hand-dug galleries can also be constructed. We primarily construct shored trenches in inner-city areas or in hard-to-reach locations.
Nailing is applied directly to slopes or walls without traditional formwork. In this way, nailing combined with shotcrete quickly and effectively stabilizes soil structures (unreinforced, reinforced, or nailed), even in hard-to-reach areas. Because it is applied directly to the reinforcement, it provides a strong, seamless finish with high compressive strength.
Berliner walls are suitable for retention in smaller construction pits. These walls can be installed quickly, cause minimal vibration, and are easy to adapt to the shape of the construction pit.
Diaphragm walls are in-situ cast concrete walls (panels) created by excavating vertical trenches. During excavation, the trench is filled with a support fluid, which is then replaced by reinforcement and concrete. They provide a robust solution for deep construction pits of 30 meters or more.
Anchoring and shoring
Anchoring (cables, rods, or self-drilling) provides stability for underground structures and retaining walls.
With permanent anchors, the steel is designed to withstand lower stresses and is protected against corrosion. They can last up to 100 years and are well-suited for the excavation of a canal or dock.
Nails (rods) are often installed in multiple layers, forming a stabilizing foundation together with the retaining wall. Ideal for steep walls or limited workspaces.
Strut frames (stross) provide temporary or permanent support for walls during deep excavation work and reliably absorb horizontal soil pressure. They can be used flexibly in a variety of building site conditions. They are the ideal solution for minimizing impact on nearby buildings.
Below the excavation level (ground level), VHP grout piles are installed to serve as underground supports—also known as struts—for retaining and waterproof walls. Other common terms include CSM secant piles and diaphragm walls.
Underwater concrete is used as a framework or support, for retaining and waterprooof walls (CSM secant piles and diaphragm walls). After the construction pit has been excavated underwater, the underwater concrete is poured. Once the concrete has cured, the water can be pumped out of the construction pit.
Soil improvement
Gravel cores can significantly improve the bearing capacity of the original soil layers by compacting the subsurface. This also reduces potential settlement.
In rigid encasements, precast concrete elements are installed at the required depth and covered with a distribution layer (LTP – Load Transfer Platform). This is a commonly used solution for industrial floors.
Compaction grouting involves filling the pores (voids) in the subsurface with a grout mixture. In suitable subsurfaces, this technique improves the bearing capacity and has a positive effect on settlement behavior.
Targeted injections beneath and alongside existing structures fill voids and washouts in the subsoil. Injections are frequently used as a (temporary) solution to stabilize existing structures.
Deep foundations (piles)
Helix piles are soil-displacing screw piles with a helical shaft that are installed without vibrations. They are suitable for efficient load transfer in soils of varying composition, from residential buildings to wind turbines or tank farms. These piles are very common for the typical soil conditions in Belgium. Our technology is technically approved with ATG 3267 certification.
Torx piles are soil-displacing screw piles with a smooth shaft that are drilled into the ground without vibrations. They are suitable for efficient load transfer in soils of varying composition, from residential buildings to wind turbines or tank farms. These piles are very common for the typical soil conditions in Belgium. This technique has been technically approved under ATG 3264 certification.
A vibro pile is driven into the ground, with or without a widened base (DCIS—driven cast in situ). The resulting void is filled with concrete. This type of pile is characterized by a high bearing capacity at the shaft and tip.
The prefab, reinforced concrete pile is driven into the ground to the specified embedment depth using an adjustable hydraulic hammer. This type of pile is ideally suited for penetrating soft surface layers, with direct load transfer to the deeper, load-bearing soil layers.
CFA stands for Continuous Flight Auger and is uncased. The cased version is called a Cased Continuous Flight Auger. (C)CFA piles are ideal for foundations in urban or sensitive environments. They combine high load-bearing capacity with minimal impact on the surrounding environment.
Micropiles are small-diameter grout piles. They can also be installed at an angle and even through existing foundations, which makes this technique ideal for urban projects.
Drilled piles with soil removal and temporary casing—whether fully or partially—can safely transfer heavy loads to deeper, stronger soil layers.
What you need to know:
In-house design and engineering
Our in-house design and engineering department designs, combines, and optimizes the techniques to be used. In addition, it models out your risks before construction begins.
Complex terrain? No excuse
We make it possible to build foundations in soil with low bearing capacity and challenging environments. And we do so safely.
Turnkey construction pit
From new construction to renovation, all the necessary technologies are seamlessly integrated.
Proven quality
We bring decades of geotechnical expertise and knowledge of regulations to the table.
Strong network
We bring in the necessary partners from our network for earthworks, groundwater lowering, shoring frames, and water glass injections.
Specialization in diaphragm walls
D&S Contractors is a subsidiary of Smet Group in partnership with DEME and STEIN. D&S focuses on diaphragm walls and CB (cement-bentonite)-walls. Together, we carry out large-scale infrastructure projects using an efficient and innovative approach.