Gob side entry failure mechanism and control of bolt-grouting in three soft coal seam

According to the field investigation and experiments on a typical gob side entry-material roadway of working face 4606 in Liangjia Coal Mine,the failure mechanism of surrounding rock under original supporting plan was ana- lyzed. The complex structure of coal seam, the easy expansion and softening of surrounding rock, large destruction scope,serious arch deformation,and ineffective support were the main causes of roadway failure. Taken bolt-grouting support as a core measure,two supporting test schemes,namely U type shed+grouting bolt+grouting cable and grouting bolt+grouting cable,were proposed. The results show that the surrounding rock deformations are less than 37% com- pared with original supporting plan. U type shed does not play an obvious role in controlling surrounding rock,there- fore,the grouting bolt + grouting cable can replace U-type shed.