Analytical Predictions on the Ground Responses Induced by Shallow Tunneling Adjacent to a Pile Group

Abstract

Prevalent buildings are supported by pile foundations in urban areas, and the importance of nearby excavation prediction is indisputable due to various engineering accidents caused by the density of urban buildings and the complexity of the underground environment. Recently, a case of tunneling adjacent to a pile group has received a lot of attention from the research community and engineers. In this study, a mechanical model of a shallow tunnel adjacent to a pile group is established. The proposed stress-release function is taken as the stress boundary condition of the tunnel periphery. Considering the pile group, the elastic stresses are calculated by complex variable theory, combined with the Mindlin’s solution. Then, the new analytical solutions to stress are obtained to predict the stratum responses induced by tunneling adjacent to the existing pile group loads inside the stratum in a gravity field. Ultimately, this study provides parameters to analyze their influence on ground stress and potential plastic zone, such as the stress release coefficient, pile group locations, and soil parameters. This research provides a theoretical basis for stratum stresses’ prediction in shallow tunneling engineering fields when tunneling adjacent to a pile group, and it can be applied to the construction of resilient cities.

Keywords

• adjacent crossing
• complex variable theory
• pile group
• shallow tunnel
• plastic zone