| 摘要 |
PCT No. PCT/FI90/00231 Sec. 371 Date Mar. 17, 1992 Sec. 102(e) Date Mar. 17, 1992 PCT Filed Sep. 27, 1990 PCT Pub. No. WO91/05137 PCT Pub. Date Apr. 18, 1991.An apparatus and a method for drilling a tunnel utilize hydraulic means comprising a cylinder and a piston to enable independent adjustment of the driving force acting on the protecting tubes and the driving force acting on the drilling tool/conveying tubes. The hydraulic means acts as a thrust bearing and moves freely in the longitudinal direction of the drilling apparatus in response to forces acting on the drilling tool which are detected as changes in pressure in the hydraulic means.
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