| 摘要 |
<p>PURPOSE:To improve the safety of refuge-pit widening construction by a method wherein the lock bolt of a refuge pit is extracted, the periphery is widened while a shelter is led out and used as a guard tunnel at the location of construction and the shelter is housed after the completion of construction. CONSTITUTION:In the method of widening construction in which a refuge pit is broadened and a tunnel for a main track is executed, the lock bolts 6 of the refuge pit 2 are extracted. The periphery is excavated and broadened through the method of mini-bench construction, while a movable shelter 9 temporarily placed in the refuge pit 2 previously is drawn out, and a guide tunnel connecting the refuge pit and an existing widening position is formed. Widening execution at the place is completed, and the shelter 9 is moved forward and housed in the refuge pit 2. A peripheral anchoring material is broken in a rotating hollow bit and the lock bolts 6 are extracted. Accordingly, the widening construction of the refuge pit can be conducted safely.</p> |
