EFFECTS OF TUNNEL EXCAVATION ON EXISTING MASONRY STRUCTURES

Abstract

 In this study, model tests were conducted on a masonry structure model to investigate the mechanical effects of a shallow tunnel excavation on a neighboring masonry structure. Tunnel excavation was simulated by lowering a trapdoor, and the relative horizontal position of the masonry structure and tunnel, overburden height, and the shape of the masonry wall were varied to observe the deformation of the masonry structure and the reaction of the surrounding ground. The results showed that the effect of tunnel excavation on the masonry structure is governed by the lateral spacing between the masonry and tunnel: a) Excavation in the ground of the front side of the masonry causes deformation in the form of masonry sinking and overturning; b) Excavation directly under the masonry causes deformation so that the masonry sinks vertically down with the ground; and c) Tunnel excavation on the backfill side of the masonry wall causes deformation in the ground, including the masonry, where a circular-slip surface is generated in the ground including the masonry.