Through the anti-explosion model tests

the deformation and steady state of large span unlined tunnel and bolting and shotcrete lining supported tunnel under explosive plane wave are studied. This paper introduces the principle and method of model test. Based on the test data

the stress characteristics of surrounding rock

deformation behavior of tunnel wall

and the fracture morphology as well as bearing capacity of tunnel are analyzed. Research shows that under the design condition and overload condition

when tunnel supported by bolting and shotcrete lining

vertical stress in side wall

acceleration peak value of tunnel vault

peak and residual value of the displacement of tunnel vault

and peak value of hoop strain on tunnel wall are less than unlined tunnel. After overload test

unlined tunnel is damaged badly and loss of bearing capacity; but bolting and shotcrete lining supported tunnel is damaged slightly; the bearing capacity can be increased by 60%.