Influence of stress relief due to deep excavation on a brick masonry wall: 3D numerical predictions

Abstract

The effects of tunnel construction on existing brick masonry walls have been extensively investigated, but the influence of deep excavation-induced stress relief is seldom reported in the literature. This paper presents a three-dimensional study to investigate damaging effects on a brick masonry wall (constructed parallel to the diaphragm wall) due to deep excavation at different depths. In addition, the effects of the wall orientation (i.e., orthogonal to the diaphragm wall), wall locations with respect to the deep excavation, and sand density were examined. The hypoplastic sand model was used to capture soil behaviour. The brick masonry wall was modelled with a micro-modelling technique. The traction-separation behaviour of cohesive elements was employed to model the mortar joints. It was found that the maximum settlement was induced at the mid-part of the wall parallel to the diaphragm wall. The induced settlement resulted in developed cracks in the wall. In the orthogonal case, the wall was bended downward, behaving like a cantilever beam. Negligible footing settlements were observed when the wall was located at a distance exceeding 0.48He (excavation depth) from the diaphragm wall. By increasing the relative density from 30% to 90%, the induced footing settlement decreased by up to 72%.