A strengthening method for a gob-side entrydriving narrow
coal pillar comprises the steps that firstly, an ultra-long horizontal
drill hole and top and bottom plate inclined
drill holes are drilled in the narrow
coal pillar inside an upper section mining roadway, the length of the ultra-long horizontal
drill hole is larger than the width of the narrow
coal pillar. A grouting off target prevention bag and horizontal and inclined grouting anchor rods are installed inside each
drill hole. A unilateral cable-stayed anchoring
system, a unilateral transverse side limiting strengthening device and a unilateral gob-side entrydriving opposite-pulling anchoring
system are formed on one side of the mining roadway, after a lower section roadway to be dug is dug, machinable rods are
cut off in the lower section gob-side dug roadway, a butt-joint short anchor rod, a cable-stayed anchoring
system and a transverse side limiting reinforcing device are correspondingly installed on the other side of the narrow
coal pillar, finally, grouting is performed on the grouting anchor rods, and prestressing force is applied to nuts. Safety and stability of the narrow
coal pillar gob-side entrydriving are effectively ensured, roadway deformation is effectively reduced, a
coal pillar plastic area is obviously reduced, and the roadway repair cost can be lowered. The structural design is reasonable and simple, construction is convenient, the strengthening effect is obvious, and the coal
recovery ratio is increased.