Effects of geotechnical conditions on surface settlement induced by tunneling in soft grounds

Tunneling through cities underlain by soft soil, commonly associated with soil movement around the tunnels and subsequent surface settlement. The factors influencing ground movement include the geotechnical conditions, tunnel dimensions and construction method. This research has been carried out to investigate the effects of geotechnical condition on surface settlement induced by tunneling. A numerical simulation has been developed for sensitivity analysis of soil movement around a tunnel and surface settlement which includes various geotechnical conditions. Geotechnical and hydrogeological parameters has been obtained from Shiraz Subway Tunnels that were excavated in soft cohesive soils below the groundwater level using earth pressure balance shield machines. This paper presents the sensitivity analysis which focuses on the soil properties and groundwater conditions. The modeling work has been performed under different conditions using a finite element method of Plaxis code, whereby the influence of soil properties has been determined. The results demonstrate that geotechnical conditions significantly affect the surface and subsurface settlements. © 2013 ejge.