Assessment of Tunneling-Induced Surface Settlement by Linear Regression Method

Settlements induced by tunneling have been a major concern in urban cities. Prediction of settlement is therefore an important task to be conducted prior to actual tunneling activities so that in case of any excessive settlement predicted, proper precautionary measures can be adopted. The paper proposes a method to evaluate the tunneling-induced surface settlement in young alluvium deposits taking into account the foundation parameters along with tunnel and soil parameters. The subsoil and tunneling parameters are taken from the Delhi metro project, and numerical modeling is used to conduct parametric studies. The model is validated with the actual field settlement data, and parameters such as foundation pressure, location of foundation, width and depth of footing, C/D ratio, diameter of tunnel, volume loss, face pressure and elastic modulus of soil are varied to assess the impact on settlement. With the results from the parametric studies, a linear regression equation is presented which is further validated with the field data. The regression equation can be used by field engineers for the preliminary assessment of settlement due to tunneling in young alluvium deposits.