Assessment method for deformation and structural damage of the masonry building caused by shield tunnelling

Excessive ground deformation caused by shield tunnelling is prone to irregular settlement and deformation cracking of the overlying building. Hence, accurately assessing the extent of damage to the building is crucial for the effective strengthening and repair of the structure. This paper presents a comprehensive case study of a metro shield tunnel conducted beneath a masonry building. We systematically monitored and investigated the settlement and crack development of the masonry building and discovered that the cracks in the masonry building were mainly situated at the maximum slope of the building settlement curve, rather than at the peak. After completion of the tunnel construction, the maximum settlement of the masonry building was 37 mm and the cracks were predominantly oblique cracks with a length of 0.6–7.6 m and a width of 0.5–5.0 mm. The maximum principal tensile strain in the walls of the masonry building was 0.153%, and the masonry building was evaluated to be moderately damaged according to the assessment criteria considering the extent of damage to the building surface. Then, we proposed a building damage assessment method that considers soil-structure interaction and subsequently verified it through finite-element results and field monitoring results. Finally, the effects of key parameters on the stiffness of the building were analyzed. The stiffness of the building was mainly affected by the opening ratio and the effective coefficient of the building cross section. These research results have significant guiding and reference values for safeguarding buildings during metro tunnel construction.