Numerically evaluate nonlinear responses of circular tunnel under gravity loading

The deflection and strain of the tunnel are essential issues for designing under gravity loading. For this reason, the present research proposes a novel technique to evaluate these responses of the tunnel easily. The nonlinear static analysis is performed to evaluate strain and deflection of the simplified form of the fixed-ended circular tunnel under uniformly distributed loading (i.e., super-structure plus sand). The range of verification results of this proposed concept is found to be (1.17 to 6.28) %, which may indicate a good accuracy of the validation. The deflection and strain show maximum values for the higher number of stories and tunnel lengths due to the increment of the self-weights of super-structure and tunnel. The ranges of variations of deflections and strains for variable tunnel lengths are found to be (2.4 to 30.3) % and (3.4 to 20.5) %, respectively, in the case of the 15-storied structure. So, these findings may help professional engineers in practice to evaluate the deflection and strain of the tunnel.