Influence of elastic resistance of wall rock on tunnel lining internal forces

Using load structure model and FEM, influence of elastic resistance of wall rock on second lining internal forces is analyzed on the basis of tunnel lining of new intercity railway. With the increasing wall rock elastic resistance, vault bending moment, spandrel bending moment and vault vertical displacement decrease gradually, and vault axial force and safety factor increase. The results show that the harder the rock, the better the tunnel lining mechanics state. With the lining becoming thicker, vault bending moment, spandrel bending moment increase, and vault axial force, vault vertical displacement and safety factor decrease. When the strength grade of concrete increases, vault bending moment, spandrel bending moment and safety factor increase, and vault axial force, vault vertical displacement decrease. However, changes of these values are very smaller. The results show that elastic modulus of concrete has small influence on second lining.