Based　on　the　comprehensive　analysis　of　the　geostress　characteristics,　rockburst　process　and　characteristics　of　the　Kamchik　tunnel　known　as　the　longest　tunnel　in　Central　Asia,　a　mechanical　model　of　rockbursts　is　established,　and　an　advanced　support　technology　for　active　rockburst　controlling　is　proposed.　The　study　shows　that,　due　to　that　the　maximum　principal　stress　of　the　geostress　in　the　tunnel　site　is　horizontal　and　close　to　the　tunnel　axis　and　that　the　tangential　stress　of　the　vault　is　maximal　after　tunnel　excavation,　rockbursts　mainly　occur　near　the　vault　in　the　Kamchik　tunnel.　The　process　of　the　rockburst　can　be　divided　into　three　stages　including　splitting　of　the　vault　rock,　brittle　fracturing　of　rock　slabs　and　block　ejecting.　The　mechanics　model　of　rockbursts　can　be　simplified　as　brittle　fracture　instability　of　a　bedded　rock　plate　of　the　vault　under　horizontal　forces.　The　critical　horizontal　stress　σcr　of　the　brittle　fracture　instability　of　the　rock　plate　is　inversely　proportional　to　the　square　of　the　unsupported　length　L　of　the　rock　plate　but　proportional　to　the　square　of　the　thickness　t　of　the　rock　plate.　The　mechanical　model　can　well　explain　the　occurrence　and　main　performance　characteristics　of　rockbursts　in　Kamchik　tunnel.　On　this　basis,　an　advanced　support　technology　by　reducing　the　unsupported　length　of　the　vault　slab　and　increasing　the　thickness　of　the　rock　slab　to　increase　the　critical　stress　of　brittle　fracture　instability,　was　developed　for　active　preventing　and　weakening　rockbursts.　Applications　of　the　technology　in　Kamchik　tunnel　indicate　that　the　effect　is　remarkable.　©　2020,　Science　Press.　All　right　reserved.