The hollow anchor bolt
is a reliable and convenient anchoring system which is applied in complicated geological conditions for rock support work. It is particularly applied in the following geological conditions, such as weathered rock, gravel layer, backfill, hard conglomerate, etc. The hollow anchor bolt is widely used in tunneling, the full seam gateway of the mine.
Under the condition of the same ground stress and the same buried depth, if the hollow anchor bolt is longer and the initial prestress force is not big enough, it can not be able to control roadway abscission layer effectively. When the length of the hollow anchor bolt is 1.5 m and the initial prestress force is about 8t, it is most beneficial for the stability of the roadway roof. When the length of the hollow anchor bolt is 2.1 m and the separation distance is 0.6m, the initial pre-tightening force which reaches 8 t can control the abscission layer of the roof under the 500 m burial depth. While if the separation distance is 0.9m, the initial pre-tightening force must reach to 20t to press the abscission layer to be fit within the scope of the roof.