Building Settlements Induced by Shield Tunneling in Close Proximity

Several construction decisions,including reasonable construction plan,tunneling parameters and building reinforcement measures,may be made by analyzing and evaluating building settlements induced by shield tunneling in close proximity.Based on a project of No.2 line of Shenzhen subway,characteristic settlements of the buildings were simulated and analyzed with software of FLAC 3D.The characteristic settlements of the buildings were also investigated by in-situ monitoring,and the effects of geology conditions and foundation types on the settlements were simultaneously studied.Results show that the settlements will increase rapidly when one tunnel is being tunneled under the buildings by the shield machine and there will be an obviously secondary settlement when the other parallel tunnel being tunneled;the secondary settlements will be also affected by the location relation between the tunnels and the building foundations;and the settlements will be much larger when the tunnel section consists of weak rock than they will be when the tunnel section consists of hard rock.