Prediction of surface settlements in subway tunnels by regression analysis

Abstract

Surface settlements developed in subway tunnels are one of the most important aspects in urban areas. Tunnelling through urban areas is principally related to soil movement around the tunnel and the surface settlement. The factors which affects this settlement may include soil conditions and tunnel parameters. This study investigates the effect of soil conditions and tunnel parameters on surface settlement in subway tunnels. A finite element numerical model has been developed for the analysis of surface settlement. In the model, geotechnical conditions and tunnel parameters were varied to calculate surface settlement. Geotechnical and tunnel parameters have been obtained from different case studies of Subway Tunnels across the world that were excavated in different types of soils below the groundwater level using different mechanism. This paper presents the regression analysis, which focuses on the soil properties and tunnel parameters. The influence of various soil properties has been determined for different condition using the finite element numerical model. The results demonstrate that geotechnical conditions and tunnel parameters significantly affect the surface settlement. Among these parameters, tunnel diameter is more sensitive to surface settlement. And the regression analysis enables an easy approach for predicting settlements in tunnel, and this prediction technique is very simple and reasonably accurate.