Optimization Study Of The Size Of Pillars In Wangeving Mining Method

As one of 'room-pillar' mining methods, Wangeving mining method has a lot of advantages, as making cutting and digging at one time, controlling the sinking of up strata and achieving mining in green way. So it is widely used in hold down coal and margin coal. Several roof disasters happened by using this mining method in ShenDong mining area. And resource waste happened because of increasing of the size. The main reason is blindness in designing pillars' size and movement of up strata. So to study supporting characters of pillars and 'pillar-roof' supporting system is the key to ensure safe produce and improve mining rate.In this paper, we synthetically use theoretic analysis, imitating calculation and spot monitoring together to study the characters of supporting pillars. We made up the 'consecutive girder' and 'supporting girder' mechanical module. Two kinds of plans were made out by mechanical calculation. According to FLAC^3D imitating spot monitoring to get the optimized size of pillars. The intension of pillars is influenced by many factors so as size offset and time offset. To chose reasonable formulas calculating and to adjust it by monitoring result is the key way to make sure supporting intension. The up load has great relationship with movement of roof. By adopting the moving by group roof structure, we got the load by calculation and roof movement monitoring. During to different size of slim pillars, we supposed 'consecutive girder' and 'supporting girder' to get different designs. And then according to FLAC^3D imitation result and monitoring result to get optimized project. The conclusion is that '8m for level pillars + 1.2m for slim pillars +1.4m for connected-tunnel protecting pillars' is the optimized project. It is proved that by using this plan roof control and mining ratio has been great improved.