Centrifuge modeling of normal faulting and underground tunnel in sandy soil deposit

Abstract

Earthquakes of large magnitudes cause fault ruptures propagation in soil layers and lead to interactions with subsurface and surface structures. The emergence of fault ruptures on or adjacent to the position of existing tunnels cause significant damage to the tunnels. The objective of this paper is to study the interaction of an embedded tunnel within a soil layer and the soil deformations imposed upon by normal faulting. A centrifuge modeling under 80-g acceleration was conducted to investigate the rupture propagation pattern for different relative tunnel positions. Compared with the free field condition, due to tunnel and normal fault rupture interactions, focused on soil relative density and tunnel rigidity in this research, found that they can dramatically modify the rupture path depending on the tunnel position relative to the fault tip. The tunnel diverts the rupture path to its sides. This study presents the normal fault-tunnel interaction with the tunnel axis parallel to the normal fault line, to examine the changes that take place in fault rupture plane locations, the vertical displacement of the ground surface with tunnel presence and the effect of tunnel rigidity and soil density on fault tunnel interaction.

Keywords
Centrifuge modelling; Tunnels; Sands; Normal fault rupture; Fault/tunnel interaction