关键词: 关键块, 煤帮响应特征, 偏应力分布, 钢管混凝土支架

Abstract: In order to solve the surrounding rock control problems in deep gob-side entry retaining, the working face 1126 with large mining height of Xingdong mine (850 m occurrence depth) was taken as research subject. Then, by means of UDEC simulation, we analyze surrounding rock response character with different subsidence amounts of key block B. Analysis result shows that: ①the deviatoric stress peak value of coal sides and its position have linear relationship with subsidence amount of key block B, and they transfer to deep part; ②deformation in deep part of coal sides has weak response to subsidence amount of key block B, and the closer to coal side surface, the more sensibility the coal sides has, therefore, there is an obvious inflection between the deep and shallow surrounding rock displacement; ③the roof subsidence amount and sides deformation amount have positive exponential relationship with the subsidence of key block B; ④along with key block B settling, broken form of coal sides experiences the following progress: unstable triangular block slide →X conjugate broken →double X conjugate broken. Therefore, some conclusions are made as follows: ①the roadside gob backfilling in can effectively limit the driving effect from key block C to block B; ②steel-concrete support can adapt subsidence feature of key block B well and has strong compression resistance and bending character; ③the high performance and high pre-stressed anchor can better improve the load capacity and deformation resistance ability of anchoring body; ④the roof truss anchor cable can be anchored in key block B that has solid and reliable anchoring basis, and, side cable can be anchored the area within the displacement inflection by passing through potential slip surface in order to restrict the side structural slip. Based on the above analysis, a collaborative control program was put forward which consists of roadside gob backfilling, steel-concrete support, roof truss anchor cable, side cable and high strength and high pre-stressed anchor. Thirty days after the entry retained, surrounding rock deformation tends to be stable. In addition, the relative displacement amount of roof and floor is 613 mm, and the other one of two sides is 374 mm, which achieves the effective control of gob-side retaining entry surrounding rock in deep mining with large mining height.

Key words: key block, coal sides response feature, deviatoric stress distribution, steel-concrete support