Masaya Hinokio

3D Effects in Excavation Problems: Model Tests and Numerical Simulations

In order to investigate the fundamental mechanisms of the generation of earth pressure and the ground movement in excavation problems such as tunneling and open excavation, 2D and 3D model tests and the corresponding elastoplastic finite element analyses were carried out. It is experimentally shown that the earth pressure and the ground movement are very much influenced by 3D effects including excavation sequence. In tunneling problems, not only the arching effect in transverse direction to tunnel axis but also the arching in excavation direction should be considered for proper predictions. In retaining wall problems, the earth pressure on the wall in 3D condition is much smaller than that in 2D (plane strain) condition, and the surface settlement at the backfill in 3D condition occurs more locally than that in 2D condition. These differences between 3D and 2D are simulated quantitatively as well as qualitatively by the analyses using an elastoplastic constitutive model which can describe typical stress- strain behaviors in general 3D stress conditions.