Effect of Tunnelling on Settlement of a Building: A Numerical Approach

Land shortages due to population growth and the sustainable development of cities have necessitated the use of underground systems. Although tunnels, which mostly provide solutions to transport problems, are frequently used today, the construction of tunnels in large cities poses significant issues. Regardless of the construction method, deformations are inevitable during tunnelling. Tunnelling machines apply pressure to the surfaces during the excavation of the tunnel surface. However, during construction, the pressures are not adjusted correctly, and deformations are observed in the ground. Since these deformations may cause major damage to the surrounding structures when they reach the ground surface, it should be calculated how much deformation may occur before construction, and necessary precautions should be taken. Therefore, this study aims to define the deformations that will occur on the soil surface. In this context, numerical analyses were performed. During the numerical studies, Plaxis 2D based on finite element method (FEM), was used to create the tunnel modelling in the clayey soil. A tunnel boring machine (TBM) was used during tunnelling in the modelling. The excavation diameter of the tunnel, cover thickness, foundation width and epicentre distance from the tunnel axis to the structure foundation were analysed in the geometric model. The effects of the geometrical parameters of the tunnel, the building and the clay soil on the displacements were determined numerically. As a result, it was determined that tunnel depth, tunnel diameter, cover thickness and foundation width are effective parameters for settlement of buildings constructed on clay soils.