Empirical evidence for estimation of subsurface settlement caused by tunneling in sand

Abstract

Tunneling is vital for augmenting urban infrastructure systems in big cities. However, the ground movement or settlement induced by tunneling can cause significant damage to the surrounding buildings, bridges, roadways, pipelines, and so on. Several theoretical and empirical methods have been proposed to estimate the settlement trough at the ground surface caused by tunneling. Subsurface settlement caused by tunneling in clay has been investigated extensively to evaluate the safety of pipelines and foundations above tunnels based on the assumption of a constant volume of the settlement trough along the depth. However, subsurface settlement induced by tunneling in sand has not been understood well due to the change of volume of settlement trough along the depth. Even though an empirical method was developed by the author based on lab-scale model test results, it has not been validated using observational data from case histories. In this study, three case histories from the literature were used to verify the effectiveness of the aforementioned empirical method for estimating the subsurface settlement caused by tunneling in sand. The comparison of the calculated results and measurements from the case histories demonstrates that the empirical method is effective to predict the subsurface settlement caused by tunneling in sand.