Experimental investigation of arching in sand using a trapdoor and miniature tunnel boring machine

Abstract

Tunnel construction inevitably causes ground movements in the surrounding soil mass, which can have a negative effect on adjacent surface and sub-surface structures in the congested urban environment. Therefore in order to avoid costly delays, it is important to have a thorough understanding of the implications of tunnel projects, one of which is the phenomenon of arching. Arching is the variation in stress associated with ground movements, and is the primary topic under consideration in this research. The arching effect due to tunnel construction has been investigated through a combination of physical models in dry sand of the active trapdoor and of the advancement of a purpose-built miniature tunnel boring machine (MTBM) through a sand mass, and through numerical modelling using commercially available software.