Effects of tunnel depth and relative density of sand on surface settlement induced by tunneling

Abstract

Tunnelling in densely populated areas is generally associated with undesirable ground movement and subsequent damage to adjacent buildings. Many parameters are contributed to the ground movements during tunnelling in which non-linear relationships are established between these parameters and ground movements. This paper presents the effects of tunnel depth and relative density of sand on surface settlement induced by tunneling by means of parametric study through finite element modelling. In this regard, tunnel excavation in sand with two different relative densities of 30% and 75% was investigated. In addition, effects of tunneling in different cover to diameter ratio of 1, 2, 3, and 4 were analysed. The results show that increasing in the value of the relative density of sand reduces the ground movements induced by tunneling. In addition, shallow tunneling in loose sand produces remarkable movements around the tunnel and on the ground surface.