Design, Construction and Performance of Single Bore Multiple Anchored Diaphragm Wall in Izmir, Turkey-Paper

Paper

Pdf Summary

The Mahall Bomonti development in Bayraklı, İzmir, required excavations up to 18.5 m deep in soft alluvial soils with a high groundwater table, near historic buildings. The temporary support system comprised an 80 cm thick diaphragm wall supported by prestressed single-bore multiple anchors (SBMAs).<br /><br />Ground investigations and single-unit and SBMA test anchors were used to establish suitable drilling, grouting, anchor configurations, and design loads. Tests demonstrated that production anchors could be designed for 650 kN, while a research test anchor achieved 1,850 kN and met creep criteria. Special drilling and grouting methods, including post-grouting and end-of-casing grouting, helped address variable soils and high artesian pressures in gravel layers.<br /><br />Approximately 2,400 anchors, totaling 55,200 linear metres, were installed. Anchors were routinely tested and locked off under a strict quality-control program. Wall movements, anchor loads, groundwater levels, and pore pressures were monitored using inclinometers, load cells, and piezometers. Measured deformations closely matched design predictions, and wall movement remained within the 55 mm limit established by the finite-element analysis, helping protect nearby historic structures.<br /><br />The project demonstrates the effectiveness of SBMA-supported diaphragm walls for deep excavations in challenging ground conditions. Compared with the original design, SBMA technology reduced the required anchoring length from 153,000 m to 55,200 m, saving up to 60% in construction time and 35% in anchoring costs.

Keywords

Mahall Bomonti

Bayraklı

İzmir

deep excavation

diaphragm wall

prestressed anchors

single-bore multiple anchors

groundwater control

soil stabilization

historic structures