松峰型立坑掘削機の性能向上について

抄録

The development of the blind raise boring machine was a joint undertaking by the Dowa mining Co. Ltd. and the Koken boring machine Co. Ltd. The first machine was introduced into Matsumine mine in 1976 and more than 30 raises were completed until the end of 1981. Basically the unit consists of a boring machine and a segment erection component. The segments of the shield frame are installed and jacked upward immediately after each boring cycle is over to keep the wall stable. Boring capacity of this machine was limited to 30m, and within this limit drill rods are strong enough with only one stabilizer located just beneath the cutter head.
This study was started to improve the boring capacity up to the depth of 60m. First of all, the data was collected in-situ, such as thrust, torque and horizontal load to the stabilizer. The theoretical examination on the basis of the in-situ measurement indicates that an additional stabilizer is necessary to prevent the buckling of the drill rod.
After the comprehensive study including experimental work by a 1/40-scale model rig to certify the safety of the new system, two test borings, where upper and middle stabilizers were used, were carried out to complete 39 and 43m raises. Though the depth of 43m is a new record for this machine, high increase rate of segment jacking force encountered at the depth more than 30m is a new source of trouble remained for future research.