ABSTRACT
Two parallel traffic tunnels will be excavated under a building which is extremely sensitive to ground subsidence. The building is founded on pillars that transfer the weight of the building to the rock surface above one of the tunnels. A numerical investigation has been carried out to study if the subsidence of the pillars and, the displacements of the tunnel boundaries will be acceptable or not. The problem was simplified assuming two-dimensional conditions and linear elastic conditions and the sensitivity to changes in the input parameters were studied. The analyses showed that the subsidence of the pillars increased by 100 % (< 0.6 mm) due to the excavation of the tunnels. Furthermore, the pillar loads resulted in a tunnel roof deformation which was 400 % (1 mm) greater than for a case without any load at the ground surface.
