Design of 20 m Deep Excavation with Permanent Anchored Secant Bored Pile Wall (SBPW) and Contiguous Bored Pile Wall (CBPW) as Retaining Structure of Cut and Cover Tunnel
Deep excavations are common for tunnel constructions in urban areas nearby existing structures. In this paper, design of deep excavation of cut and cover tunnel for Portal of dual tube Konak Tunnel in the Konak Square in İzmir, is presented. The maximum height of excavation is 20 m. At the right side of excavation section with maximum height, adjacent 5 storey masonry museum building is located. For the staged excavation of cut and cover tunnel structure, secant bored pile walls (SBPW), contiguous bored pile walls (CBPW) with and reinforced concrete deck (RCD) are designed as components of portal structure. Jet grout columns are designed at excavation basement level and under nearby museum building foundation. According the analysis results, stability of cut and cover tunnel, displacements closed the excavation, internal forces in retaining structures and settlements under nearby structure foundations are computed and checked with acceptable limits in design state.