Back analysis of closure parameters of Panet equation and Burger׳s model of Babolak water tunnel conveyance

• Convergence has been predicted in sidewall tunnel using Panet equation.
• Convergence due to face advance and time effect have been determined separately.
• Convergence due to advancing face has been determined numerically.
• Using back analysis Burger׳s model׳s constants have been determined to predict time dependent displacements.

Babolak water conveyance in north of Iran on Babolak river is under construction. Tunnel support consists of lattice girder, rock bolt, and shotcrete. According to application of classification systems RMR and Q, rock mass in the path of primitive part of the tunnel which is excavated in Marn is evaluated weak and very weak. In first part of the paper the Closure parameters of Panet equation associated with face advance and time effect of the tunnel in six different stations are determined using optimizing Levenberg–Marquardt and Trust-Region back analysis techniques on convergence instrumentation data. In second part of the paper, Burger׳s creep parameters are determined using instrumentation results in 0+603 station and Panet equation results in a back analysis performed utilizing FLAC3D. Predicted convergence results by the Panet equation are in good agreement with numerical analyses.