Abstract: Through the plane charge loading test, the anti-explosion performance of different height-to-span ratio structures under explosion load of plane charge is studied. Based on the previous structural effect tests of intense explosion, the damage characteristics corresponding to different failure grades of supporting structures in hard rock under the action of intense explosion are analyzed. The macroscopic damage forms of structures with different height-to-span ratios are described in detail and the damage mechanism of structures is revealed. The test results indicate that the damage characteristics and damage grades of three types of structures with different height-to-span ratios vary under the same loading conditions. Firstly, in the structural test section with a height-to-span ratio of 1.17, extrusion and compression-shear damage occur at the arch, and there is a moderate blockage in the tunnel. The structural test section is severely damaged. Secondly, in the structural test section with a height-to-span ratio of 1.50, the arch foot produces a through compression-shear failure zone, and the straight wall is damaged by tensile stripping. The tunnel presents medium stripping, and a large amount of concrete accumulation is formed on the bottom plate. This structural test section is moderately damaged. Lastly, the structural test section with a height-to-span ratio of 1.00 is mainly damaged by splitting and stripping, with slight stripping in the tunnel and a small amount of concrete accumulation on the bottom plate. This structural test section is moderately damaged. The comprehensive analysis shows that the structural type with height-to-span ratio of 1.00 has the best anti-explosion performance.

Key words: plane charge, structural height-to-span ratio, damage grade, damage characteristics, anti-explosion performance