Expert fields

INTRAFOR provides technical support, from project planning through to complete final design, construction engineering and the execution of works on site. The process and techniques provided by INTRAFOR include:

UNDERGROUND WALLS (to serve either as a cut-off walls or as a retaining walls)

Perth City Link, Australia

• Diaphragm wall : Retaining, supporting and/or waterproofing wall e.g. for basements, cut & cover tunnels and deep shafts, for which INTRAFOR has patented a proprietary method in order to significantly speed up construction and ensure almost perfect verticality at depths > 90m.
• Reinforced bentonite-cement slurry walls : Similar to diaphragm walls , based on steel sections plunged in bentonite-cement slurry
• Cut-off walls : unreinforced bentonite-cement slurry wall or grout curtain wall
• Soldier pile or Berliner walls : Retaining walls based on piles and horizontal lagging between them
• Continuous bored piles or secant pile walls : Constructed by alternating 'female' piles with the subsequent construction of 'male' piles.
• Nailed walls : Retaining wall using anchors for support.
• Sheet piling.

DEEP FOUNDATIONS

ICC Tower, Hong Kong

• Barrettes : Large rectangular section piles constructed using a grab bucket on a kelly or cables, or using 'hydromill' cutters, reinforced with a steel cage before concreting.
• Bored piles : Concrete piles of varying depth and diameter, reinforced with a steel cage before concreting.
• Micropiles : Drilled, small diameter piles reinforced with reinforcement bars or steel pipes, then concreted.
• CFA (continuous flight auger) or PIP (packed-in-place) : A continuous boring auger is used to drill a pile, which is reinforced with a steel cage or steel section after concreting.
• Driven piles : Steel sections or precast-prestressed concrete piles hammered down into the soil.

SOIL IMPROVEMENT

Hong Kong Link Road 03, Hong Kong

• Vibro-compaction. Granular soil is compacted by a vibrating probe.
• Stone columns : Columns made of compacted gravel to reinforce a soil. Various methods available including INTRAFOR’s proprietary bottom feed methods.
• Soil mixing : Mixing in-situ existing soil with binders (cement, lime) to obtain semi-rigid inclusions.
• Grouting : Controlled injection of a self-hardening cementitious mix through drilling rods to fill cavities and cracks, as well as to strengthen and/or waterproof the soil.
• Jet grouting : A high pressure jet, which restructures the soil by mixing it in-situ with a cement grout that forms a hardened column of soil+cement.
• Compaction grouting : Stiff, low mobility grout is slowly injected into loose soils, displacing and compacting the surrounding materials.
• Ground freezing : Soil beneath the watertable is frozen using circulation of brine or nitrogen.
• Dynamic compaction : Compaction energy is brought to granular soil through heavy tamping.
• Drainage and preloading : Used to consolidate compressive soils before construction of structure.

GROUND INVESTIGATIONS & DRILLING

• Ground investigation : To determine soil characteristics, including seismic investigations, penetrometers, drilling, crossholes and in-situ tests.
• Soil testing : A full range of techniques is available to determine the properties of a soil.
• Directional coring : Allows soil investigation following a predetermined path.
• Directional drilling : For pipe or cable laying. A hole is bored along the required alignment.

OTHERS

• Monitoring. A full range of techniques is available to monitor the behaviour of the ground or of a structure, during underground works or afterwards.
• Ground anchors (or rock anchors or tiebacks) : Drilled and grouted, post-tensioned or passive ground reinforcement system. Removable systems are available.
• Dewatering : Groundwater lowering systems for excavations, and recharging systems where necessary for ground settlement control.

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