The Deep Soil Mixing for the Galataport Project in Istanbul, Turkey-Paper

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The Galataport project in Istanbul used a combined quay-wall and ground-improvement system for the new Salipazari quay. The structure comprises a combi-wall of bored cast-in-place piles installed through permanent steel casings, supported by inclined piles at 5 m spacing, and a 1,200 mm-thick reinforced-concrete diaphragm wall.<br /><br />After construction of the quay wall, the area was backfilled with controlled gravel and cobble fill and treated with 1,500 mm-diameter tangent deep soil mixing (DSM) columns using the Turbojet method. The DSM columns were arranged on a triangular pattern, with an untreated row reserved for the future diaphragm wall alignment. The treatment was intended to stabilize loose fill before diaphragm-wall construction, reduce liquefaction risk in loose seabed sands, and create a stiff block to distribute ship loads between the quay and terminal structure.<br /><br />The paper discusses ground conditions, construction challenges, preliminary field trials, and tests of the DSM materials, including seawater and CEM IV SR cement. It also describes electronic rig controls used to automate column execution. Quality assurance included coring and laboratory testing, seismic refraction tomography, and seismic cross-hole tomography. The authors report correlations among unconfined compressive strength, static modulus, and dynamic modulus, and describe inspection of the treated ground during excavation.<br /><br />Following completion of the DSM and diaphragm wall, excavation and construction of the passenger gangway connected the quay and diaphragm wall. The project was completed with excavation to 13 m below sea level, construction of the terminal building, and removal of the temporary inclined seaside support piles.

Keywords

Galataport

Istanbul quay wall

Salipazari quay

deep soil mixing

DSM columns

combi-wall

diaphragm wall

liquefaction mitigation

ground improvement

Turbojet method