Abstract
In urban areas, tunneling may induce ground movements which distort and damage overlying buildings and services founded on different geological formations.The objective of this study is to examine the effect of horizontal distance between the center of tunnel and the surface buildings. The study has been achieved using3D-FEM with the aid of PLAXIS 3D Tunnel code. The parametric studies including the horizontal distance between centerline of tunnel and the center of loaded area by taking five different distances that as ratios of distance to tunnel diameter(X/D= 0, 1, 3, 7 and 10). Three different geological formations have been selected that clay, sand and rock. In addition, three type of surface loadings have been adopted that greenfield, uniform pressure and piles.The results show that the surface subsidence decreasing with the increasing in the horizontal distance between the centerline of tunnel and the center of surface load. The maximum subsidence occurs when the center of tunnel sited under the edge of building (uniform pressure or piles), i.e. when (X/D=1). Then, the effect of tunnel vanished when it is at a distance of (3D) from the building. The greatest effect of the distance observed in case of pile group in sandy soil by increasing of (52%) in settlement over the unloaded one. The subsidence being uniform when the centerline of tunnel coincides with the center of building (X/D=0), while a differential subsidence has been obtained when the distance increases, i.e. X/D > 0.
