Shield tunneling process and machine for constructing a tunnel

Claim 1

A SHIELD TUNNELING MACHINE FOR MILLING AND CONCRETING A TUNNEL HAVING A CIRCULAR CROSS-SECTION IN A SUCCESSION OF CYCLES OF OPERATION, SAID MACHINE COMPRISING A BASE TUBE HAVING A FORWARD END, AN ANNULAR MILLING CUTTER CARRIED BY SAID BASE TUBE AT SAID FORWARD END, A GUIDE TUBE SPACED AROUND SAID BASE TUBE AND FIRMLY CONNECTED THERETO, THE LENGTH OF SAID GUIDE TUBE BEING APPROXIMATELY ONE HALF THE LENGTH OF SAID BASE TUBE, SAID ANNULAR MILLING CUTTER BEING OPERABLE TO FORM A BORE HAVING A DIAMETER EQUAL TO THE OUTSIDE DIAMETER OF SAID GUIDE TUBE, SAID BASE TUBE AND GUIDE TUBE DEFINING BETWEEN THEM A FIRST ANNULAR SPACE, A PLURALITY OF CIRCUMFERENTIALLY SPACED, AXIALLY EXTENDING HYDRAULIC JACKS DISPOSED IN SAID FIRST ANNULAR SPACE AND CONNECTED TO SAID BASE TUBE, SAID BASE TUBE EXTENDING BEHIND SAID GUIDE TUBE TO DEFINE WITH SAID BORE A SECOND ANNULAR SPACE, SAID BASE TUBE BEING FORMED BEHIND SAID GUIDE TUBE WITH PERIPHERALLY SPACED OPENINGS COMMUNICATING WITH SAID SECOND ANNULAR SPACE, MEANS FOR INTRODUCING CONCRETE THROUGH SAID OPENINGS INTO SAID SECOND ANNULAR SPACE, SAID JACKS COMPRISING JACK PISTONS HAVING RING SEGMENTS SECURED THERETO, SAID JACKS BEING OPERABLE TO FORCE SAID RING SEGMENTS AGAINST CONCRETE PREVIOUSLY INTRODUCED INTO SAID SECOND ANNULAR SPACE AND TO ADVANCE SAID ANNULAR MILLING CUTTER, A ROTATABLY MOUNTED DOUBLE CYLINDER SURROUNDING SAID BASE TUBE AND COMPRISING TWO CYLINDER SECTIONS HAVING A FORWARD END, AND AN ANNULAR WEB CONNECTING SAID CYLINDER SECTIONS AT SAID FORWARD END, AND MEANS FOR ROTATING SAID DOUBLE CYLINDER, SAID MILLING CUTTER COMPRISING MILLING CUTTER TOOLS CARRIED BY SAID DOUBLE CYLINDER.