Suez Canal Underpass: 260.000 M² of Deep Diagraphram Wall Excavation Experienced with LWN at Almost 360°-Paper

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The case study describes foundation works for new road tunnels beneath the Suez Canal at Port Said, Egypt. The project included approximately 260,000 m² of diaphragm walls for tunnel shafts, access roads, TBM launch areas and canal-bank protection. Panels were generally 1.2 m thick and 2.8 m long, with excavation depths reaching 70 m. Ground conditions consisted mainly of clay with sand lenses, underlain by sand and gravel.<br /><br />Contractors used both conventional single-panel excavation and larger multiple-panel sequences. Hydraulic grabs excavated primary panels, while trench cutters formed interlocking closure panels. Deep, overlapping excavations required specially weighted bentonite slurry containing barite; two treatment plants, each rated at 500 m³/h, supplied the works. Reinforcement cages were assembled on site, and concrete mixes were designed for strength and resistance to salt-water exposure.<br /><br />A major focus was the Liebherr HS 8100 HD crawler crane fitted with a Leffer XY-360 hydraulic grab and Active Deviation Control (ADC), integrated with the crane’s Li-Tronic system. The grab could actively correct alignment in two directions, with reported verticality control to about 1:800. In recorded comparisons, it achieved an approximate penetration rate of 40 cm per cycle, versus 25–30 cm for the other tested grabs. The authors also reported substantially longer rope life for hydraulic grabs than for mechanical grabs, and fuel consumption below 20 litres per hour for the HS 8100 HD.<br /><br />The project demonstrated the challenges of deep diaphragm-wall construction, particularly cutting hardened, reinforced concrete at panel joints, where progress could fall to only millimetres per minute. The authors conclude that hydraulic grab systems with active alignment control offer important advantages for deep excavations, including improved accuracy, reduced rope wear and less dependence on highly experienced operators.

Keywords

Suez Canal tunnels

diaphragm walls

Port Said Egypt

deep excavation

hydraulic grab

Liebherr HS 8100 HD

Active Deviation Control

bentonite slurry

trench cutter

TBM launch area