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Prediction of the Longitudinal Uplift of an Underwater Shield Tunnel During Canal Excavation
1 School of Civil Engineering, Southwest Jiaotong University 2 Hebei University of Science and Technology 3 Department of Civil Engineering, Hebei Jiaotong Vocational & Technical College 4 School of Civil Engineering, Shijiazhuang Tiedao University
Abstract A prediction model for the longitudinal uplift of an underwater shield tunnel during the excavation of a canal was set up and solved based on the bending differential equation of the elastic foundation beam, compatibility equations of deformation, rotation angle, shearing force and bending moment, and its boundary conditions. The results show that the analytical solutions obtained by the prediction model are consistent with the numerical solutions within a maximum error of 2.7%, and can therefore be used to predict uplift in similar projects. The longitudinal uplift of the shield tunnel decreases nonlinearly with the increase of the ground reaction coefficient, while it is not affected by the reaction coefficient when the ground reaction coefficient reaches 10 000 kN· m-3. In practical engineering, it is possible to keep the ground reaction coefficient around 10 000 kN·m-3 by backfill grouting to realize a balance between economy and safety.
Abstract：
A prediction model for the longitudinal uplift of an underwater shield tunnel during the excavation of a canal was set up and solved based on the bending differential equation of the elastic foundation beam, compatibility equations of deformation, rotation angle, shearing force and bending moment, and its boundary conditions. The results show that the analytical solutions obtained by the prediction model are consistent with the numerical solutions within a maximum error of 2.7%, and can therefore be used to predict uplift in similar projects. The longitudinal uplift of the shield tunnel decreases nonlinearly with the increase of the ground reaction coefficient, while it is not affected by the reaction coefficient when the ground reaction coefficient reaches 10 000 kN· m-3. In practical engineering, it is possible to keep the ground reaction coefficient around 10 000 kN·m-3 by backfill grouting to realize a balance between economy and safety.
2015, Vol. 52 