Tunnel-driving machine and method of using this machine

摘要

Tunnel-driving machine in which abutment arms are provided which extend obliquely forwards and in the direction of the tunnel wall. At their front ends, the abutment arms have pressure devices which can transmit the thrust for the boring head to the end face of the tubbing, the boring head being retractable into the interior space of the machine by means of the abutment arms and the pressure devices.