Surface settlement assessment during urban tunnelling, especially in the presence of saturated bodies, is crucial for the safety of nearby structures and utilities. This study uses a finite element-based Rocscience (RS2) tool to obtain the surface settlement trough for the two cases, viz. tunnel hits a water pocket (saturated body) and grouted water pocket. In the case of tunnel hits a water pocket, the maximum surface settlement was found to be 31.6 mm, while for the grouted water pocket, it was 16.4 mm, which is nearly 50% less than the latter case. Furthermore, the support capacity curve findings showed that the support lining is unstable when the tunnel hits a water pocket; however, in the grouted water pocket case, the liner’s safety exceeds the design factor of safety. In addition, the combined maximum surface settlement obtained by the numerical method (RS2) is validated with the O’Reilly and New method, based on Peck’s classical empirical theory. It is found to be closer to it by 6%, indicating good agreement. The findings are also compared with a few analytical studies, including Limanov’s, Sagaseta’s and the Gonzales-Sagaseta method. Limanov’s and Sagaseta’s, methods showed comparable results to the present study; however, the Gonzales-Sagaseta method underestimated the results. Finally, the applicability of the RS2 method is verified by conducting the parametric study on tunnel geometry (depth and diameter), and the results compared to analytical methods. The application of predicted surface settlement guides the tunnel engineer from the future consequences regarding the destructive effects of adjacent structures and facilities, particularly in the presence of water bodies.
