Numerical Investigations of Footing Width Influence on the Surface Footing-Tunnel Interaction Analysis

With the increasing in urbanization, tunnels became a necessity for major cities like Cairo and a large number of tunnel projects had to be undertaken worldwide. Tunnels are constructed to resolve transportation and sewerage problems and may pass near or under existing buildings. Conversely, constructing structures on top of existing tunnels could cause
stresses increasing within the soil mass, which sequentially increase stresses transferred to and deformation of the tunnel lining. The interaction between the surface footings and underground tunnels depends upon several factors including the relative dimensions of the surface footings and tunnel as well as depth and eccentricity of the proposed tunnel. In this paper, a numerical investigation of a surface footing-soil-tunnel system is performed using the ABAQUS finite element code. To validate the numerical procedure and material constitutive models used in the present work, a comparison with relatively small scale experiments is first performed. The results obtained illustrate that an agreement between numerical and experimental results is reasonable. Further numerical investigations have been carried out for the different factors affecting the system response.