Assessment of changes in elasticity module and soil Poisson’s Ratio on applied forces to tunnel lining during seismic loading

ABSTRACT: Since one of the major problems in developing the urban areas is heavy traffic, using underground spaces such as, subways is one of the priorities in densely populated cities. Thus, excavating subway tunnels by T.B.Ms in urban districts is of high importance. Designing tunnel linings is performed with respect to static and dynamic loads. On the other hand, changes in soil elasticity module and Poisson’s ratio during the earthquakes play a significant role in changing the applied forces resulted by the loads. In the present study it is tried to investigate the changes in soil elasticity and Poisson’s Ratio during dynamic loading that affect tunnel linings. Hence, the amount of axial force, and decrease in shear force and bending moment in static and dynamic states are compared by changing the above-said parameters. According to the obtained results, increase in elasticity module leads to increase in axial force, shear force and bending moment during the earthquake. Amounts of changes in seismic load are remarkable and have a significant effect on designing tunnel linings…