ABSTRACT
Whenever a building is positioned above the excavating tunnel, the building must be examined for cracks running both normal to and in the plane of the tunnel axis. In the classical two-dimensional (2D) deep beam theory, only the transverse section of the building to the tunnel axis is considered. A building which is narrow in the direction orthogonal to the tunnel axis may not experience serious cracking parallel to the tunnel centre line, but a building that is long both parallel to, and transverse to, the tunnel centre line may experience cracking in the two orthogonal directions (Attewell 1978).
