Soil-foundation contact models in finite element analysis of tunnelling-induced building damage

Finite element analysis provides a potentially useful option for assessing the likely extent of damage to existing buildings, caused by nearby tunnelling activities in an urban environment. The paper describes a 3D finite element model for masonry buildings founded on shallow strip footings, affected by single or twin tunnels in a typical London geological formation. The building is represented in the model as an isolated single facade. The paper focuses particularly on modelling the soil-foundation contact behaviour. The soil-foundation interface is represented by a Coulomb friction model, with a contact formulation allowing gapping. Results indicate that the normal traction redistribution along the length of the footing, the relative horizontal movement between the soil and the footing, and the tensile strain induced in the building facade are sensitive to the assumed value of the friction coefficient. The computed horizontal strains in the footing are typically smaller than those in the adjacent soil.