Complicated 3-Dimensional (3D) parametric analyses were carried out (by using Finite-Difference models of more than 80000 elements) in order to investigate the tunneling excavation and temporary supportinduced surface settlements in the case of a shallow (depth 18m) tunnel (height 9m and width 18m), which is excavated by using the “NATM” method of tunneling. In the parametric studies the detailed excavation and temporary support of the tunnel is simulated, as well as diaphragm pile-walls that are used as temporary support for the excavation of deep pits. The position of the pile walls (in the parametric analyses) varies in both sides of the tunnel and is producing a geometrical asymmetry. As a result of the pile-walls presence in the sidewalls of the tunnel, a non-symmetrical shape of the surface settlement trough is obtained. The shape and the magnitude of the 3D settlement trough are calculated for different positions and stiffness of the pile-walls.