Simplified analysis method for predicting the influence of deep excavation on existing tunnels

Abstract

Abstract A deep excavation has a significant influence on existing tunnels. However, there is currently a lack of simple and practical assessment methods for predicting this influence. In this paper, a simplified model is proposed to predict the displacement of existing tunnels caused by a laterally-adjacent deep excavation in the soft soil layers. Using numerical simulations, large quantities of artificial data are generated for a regression analysis of tunnel displacement and its influential factors, including the excavation width, excavation depth, system stiffness, soil properties, and tunnel location relative to the excavation. Then, multiplicative regression equations are established to compose a simplified prediction method. The simplified model is verified using artificial data and case histories not included in the development of the proposed model. The results demonstrate that the simplified model can accurately predict the tunnel displacement caused by deep excavations in soft clays.