Static analysis of interaction between twin-tunnels using Discrete Element Method (DEM)

The development of transportation in large cities requires the construction of twin-tunnels or the construction of new tunnels close to the existing ones. since both the relative position of tunnels and the construction procedure affect the soil movement, this paper presents analysis of this issue with a particular interest for the optimization of both the relative position of the twin-tunnels and the construction procedure. since the soil is composed of discrete particles with different sizes, modeling using finite element methods based on the mechanics of a continuous medium is not completely consistent with reality (especially, modeling of confining effect with depth). therefore, in this study, discrete element method is used to model the discontinuum nature of soils. for these concerns, using software pfc2d based on discrete element method (dem), the static analysis of circular twin-tunnels has been performed, and inuence of the two factors on the soil settlement resulting from the tunnel construction has been investigated. analyses were conducted for three configurations of the twin-tunnels: aligned-horizontally, vertically, and inclined. the results are compared with the fem results. the comparison shows inuence of modeling the discontinuous nature of coarse-grain alluvial soils with respect to continuous media modeling.