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

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The Galataport project in Istanbul required a new Salıpazarı quay and an underground cruise terminal on loose, variable coastal soils with a high liquefaction risk. The quay’s support system combines a combi-wall, a reinforced-concrete diaphragm wall, and deep soil mixing (DSM). The DSM treatment was designed to stabilize reclaimed fill, reduce liquefaction risk in underlying silty sand, and form a stiff block that transfers ship loads between the quay and terminal structure.<br /><br />Trial columns were used to determine construction parameters. Because the fill and natural soil required different cement contents, production columns used a two-zone treatment. The initial design targets were an average unconfined compressive strength (UCS) of 5 MPa and elastic modulus of 500 MPa. Shell-rich sand produced lower UCS results than expected, so the shoring design was reassessed and the UCS target reduced to 2.5 MPa. Final quality-control testing met that revised target, while measured elastic moduli exceeded the specified value. Seismic refraction and cross-hole tomography indicated dynamic Young’s moduli of 4–6 GPa—over 100 times those of the untreated soil—and showed no weak layer in the shell-rich zone.<br /><br />Automated monitoring systems controlled drilling and grout delivery, adjusted operating speeds to soil conditions, and supported centralized site supervision. Coring and excavation also provided direct checks of the treatment. Buried debris, including rubble, tires, and old ship fittings, sometimes obstructed DSM columns; affected areas were treated instead with jet grouting.<br /><br />The authors emphasize thorough seabed and soil investigations, detailed field trials, and adaptable construction methods, particularly at coastal sites with uncontrolled fill. They also highlight that advanced equipment and electronic controls must be combined with expert judgment and close coordination among the client, consultant, and contractor.

Keywords

Galataport

Istanbul quay

underground cruise terminal

deep soil mixing

liquefaction risk

combi-wall

diaphragm wall

soil stabilization

dynamic Young modulus

quality control testing