Longitudinal Settlement Profile in Shallow Tunnels in Drained Conditions

Shallow tunneling in urban areas causes settlements whose measurement, prediction, and prevention are the most important tasks facing tunneling engineers. Researchers have proposed several analytical, semianalytical, and empirical equations for these tasks. Because of the significance of the transverse settlement trough, many correlations have been suggested for its dependency on various parameters; however, investigation into the longitudinal settlement profile is still lacking. The purpose of this paper, therefore, is to study the effect of three important parameters, namely overburden depth, round length, and cohesion, on this profile in drained conditions using a three-dimensional FEM and to propose a correlation thereto. Comparison with the monitoring results from two tunnel case histories reveals the suitability of the correlation in predicting the longitudinal settlement profile in shallow tunnels. (C) 2014 American Society of Civil Engineers.