FLEM-DEM結合解析の積層導坑トンネルの応力・変形解析への適用

抄録

This paper deals with FLEM-DEM coupled scheme for the analyses of stress and displacement of geotechnical problems. The discontinuous domain in a given problem is modelled as a set of distinct element blocks of DEM. The continuous domain is partitioned by a finite difference grid as a FLEM grid. The FLEM, which is proposed by us, is one of the numerical methods that can be used to analyze large deformation problems. The two methods are coupled together by satisfying the equilibrium conditions of traction and continuity of displacement at interface between the two domains, at each iteration of the solution process. This means that the coupled scheme is well suited for considering joint slips and separation as well as large rotation and displacement of blocks.
Verification of the scheme is demonstrated through the analysis of a stacked-drift-type tunnel. The stacked-drift-type tunnel is a new one which is now under investigation as a large cross-section tunnel over 20m in diameter. The numerical results of the contact force between the drifts and force acting to the tunnel as well as the stresses in the surrounding ground are summarized together with the results from a series of centrifugal tests of the tunnel model. It may be concluded that the circumferetial forces acting to the drifts are important to understand the stress-displacement relationship of tunnel.