An innovative and simple approach for predicting tunnelling-induced ground movements semi-analytically

ABSTRACT A semi-analytical elastic solution for predicting tunnelling-induced ground movements in clayey media is presented in this study. This study modelled the non-uniform ground movements (or non-uniform ground loss) around the tunnel cavity using the Gaussian distribution function. A new approach is proposed to model the tunnel peripheral displacements other than the simplistic trigonometric functions. It is shown that by modelling the ground loss in an elliptical fashion, (i) better prediction of ground surface settlements is obtained compared to the circular ground loss in some cases, while (ii) in other cases, circular ground loss gives better predictions. This indicates that both these approaches should be used to predict the ground surface settlements. Further, the ground displacements observed in East-West Metro, Kolkata, are discussed as a case study. The semi-analytically obtained displacements give good conformity with the observed field measurements in East-West Metro. This solution is much simpler to follow and can be easily employed in a code compared to the complex variable method or airy stress function method.