The ground Full relaxation and displacements by phased excavation order

Abstract: Model tests were conducted to examine the load transfer and the aching effects on the behavior of the ground around the tunnel due to the phased excavation order at the tunnel face. Tests were conducted in the trapdoor tests apparatus developed by Terzaghi(1946) for 16 cases with different overburdens, which were 0.5D, 1.0D, 1.5D, 2.0D respectively by changing aspects of differential settlement. The load-displacement relationship (Q-s Curve), the transverse load transfer and the displacement shape induced by the move-ment of a trapdoor in asymmetrical displacement due to the phased excavation order were evaluated. Assessment of the trapdoor mechanisms would be applied design the support pat-terns and the excavation method.