Prediction of ground surface settlements by analytical and finite element methods

Abstract

The soil surrounding the excavation of shallow tunnels may experience destructive deformation near the tunnels. Particularly in densely populated areas where land resources are scarce, ground subsidence caused by tunnel excavation, which in turn affects surrounding structures, deserves more attention. Over the past few decades, various research methods for predicting the maximum vertical ground surface settlement have been proposed. In this study, an empirical estimation method, an analytical technique for evaluating ground movements, and a numerical simulation method using Plaxis 2D, a finite element model software, were selected as prediction approaches for ground surface settlements. Subsidence measurements were obtained from a metro tunnel excavated using an earth pressure balance shield tunnel boring machine and constructed in a dense sandy gravel layer. Comparison of the monitored deformations with the estimation results calculated by different prediction approaches showed that the maximum vertical settlement of the ground surface evaluated by the analytical technique and finite element model agreed well with the actual measured values. This suggests that these two prediction methods have the potential for conserving nearby structures during the construction of underground infrastructures.