PURPOSE: To shorten working hour and enhance economic efficiency by installing a glass fiber rock bolt into a face and excavating its surrounding area and pushing back the projected bolt and continuing the excavation.
CONSTITUTION: A triangle-shaped plate 7b, which is designed to hold back its rotary motion or its deviations in a tunneling direction, is welded with the rear part of a rod-shaped part 7a of an H-steel, for example, thereby preparing arrow-shaped bolts 7. Then, the number, pitches and a placement range of bolts 7 are specified so as to meet with a natural ground condition. They are driven into a face with a breaker having a pushing attachment. After the bolts 7 are driven and buried, the excavation of cutting face is advanced, avoiding the bolts 7. The exposed bolts 7 are pushed in with the breaker each time in conformity with the progress of the cutting face. The excavation of a tunnel is thus continued by repeating these processes.
CHIKAMORI HIROSHI
HISA TATSUO
