Important aspects when modelling the interaction between surface structures and tunnelling in sand

摘要

Tunnelling in urban areas continues to increase and has highlighted the need for a better understandingrnof the impact of tunnel excavations on existing buildings. This paper considers the influence of surfacernstructures on ground displacements caused by tunnelling in sand through finite element modelling and centrifugerntesting. First, the importance of modelling assumptions is evaluated by comparing centrifuge modelling resultsrnto finite element modelling results for various soil constitutive models: both a Young’s modulus that linearlyrnincreases with depth and a power law relation between the soil stiffness and stresses are considered. Second, thernmost effective soil constitutive model was used to perform a sensitivity study on the effect of different factorsrngoverning the structural response. In particular, the effect of the building stiffness andweight on the modificationrnof soil displacements is investigated by introducing a simple surface structure. The use of a no-tension interfacernbetween the building and the soil was found to be essential to investigate the effect of weight on gap formationrnbetween the soil and the structure, as observed during the experimental tests. Results show the importance ofrnconsidering the relation between the building weight and the relative stiffness between the building and the soilrnwhen assessing the structural response.