Adaptability theory of roadside support in gob-side entry retaining and its supporting design

As key part of no coal pillar mining,gob-side entry retaining is successfully applied in thin or medium thick- ness seam. However,it is not effective for quickly subsidence and dynamic pressure of hard roof beam. In order to solve the problem,the subsidence law was discussed and adaptability theory of roadside support in gob-side entry retaining was preliminary studied. The theory was explained by deformation and load. So,a new kind of roadside support model was constructed named “flexible-hard” combined wall,in which flexible materials were used to slow down hard roof beam quickly subsidence and hard materials were used as main support to afford its force. Then,the heights of flexible layer and hard layer were shown. The rheological synergy between caved rock and roadside support was used to esti- mate compaction stability time of caved rock and analyze rheological properties of hard supporting layer. By field test, it was successfully applied in hard roof and made great progress in green mining.