FLAC^3D program and its applications in couple problem between primary support design and rock wall condition in double-arch tunnel

In order to acquire mechanics response between rock wall and support frame system in optimum-design to adjust working stage in time it was necessary to simulate 3D model of tunnel support design. The FLAC^3D model and different support parameters were used to simulate and analysis the stress and displacement in the wall rock mass during primary support of the double-arch tunnel in this paper, the stress and displacement law of the supporting structure was achieved as well. Some beneficial results were gained and offered the optimized working procedure to the double-arch tunnel to direct working, great economic benefit was attained as well.