KASKTAŞ A.Ş., fully owned subsidiary of ENKA, started the excavation works of the reinforced concrete anchor block structure on the European side of the Çanakkale 1915 Bridge, with a volume of 68,000 m³ in May 2018. Within the content of the European Anchor Block Project, with a maximum excavation depth of 46 m; slope stability protection, excavation and dewatering works were completed according to the target work schedule in a very heterogeneous soil profile; consisting of Miocene-based sandstone-mudstone layers and Holocene deposits containing gravelly sand-clay units especially on the sea side.
Within the scope of project; 170,000 m³ of excavation work, 10,000 m rock bolts, 12,000 m² of shotcrete applied with ±1cm construction tolerance , 431 secant piles and 28 dewatering wells were executed. In order to verify in-situ design capacity of the rock bolts, 8 preliminary pull-out tests were performed, moreover a total of 17 verification tests were also performed on each side of the excavation pit and each excavation stage prior to the commencement of the production rock bolts. In order to obtain detailed information about the calculated and observed deformations of the excavation support system, deformations are closely monitored with regular readings taken from the measurement system consisting of 4 inclinometers, geodesic measurements involving 36 ground survey markers installed on exposed faces of the slopes and 16 observation wells. It was observed that the measured deformations were well below the deformation values predicted by the Designer COWI for the 46 m deep excavation.
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