Tunnel boring machine

A tunnel boring machine for boring a tunnel having tunnel lining structure areas in portions of the tunnel associated with unstable ground and having unlined areas in portions of the tunnel associated with stable ground, the tunnel having a central longitudinal axis, and having generally circular tunnel cross sections perpendicular to the central longitudinal axis, the tunnel cross section having a pitch axis oriented generally perpendicular to the direction of gravitational force and intersecting the central longitudinal axis and having a yaw axis intersecting the central longitudinal axis and the pitch axis and perpendicular to both, the tunnel having an end face and a peripheral sidewall with lined and unlined portions;

• the tunnel boring machine comprising:
• rotatable cutting wheel means positioned at the front end of the machine having a central axis of rotation adapted to be selectively located at a position substantially coaxial with an associated portion of the tunnel central longitudinal axis the cutting wheel being selectively engageable with the tunnel face for cutting material away from the tunnel face to elongate the tunnel in a forward direction;
• rotation means operably associated with said rotatable cutting wheel means for selectively causing rotation thereof in a cutting state of operation and for selectively stopping rotation thereof in a noncutting state of operation;
• extendable and retractable central thrust rod means having a central thrust rod longitudinal axis positioned in substantially coaxial relationship with said rotatable cutting wheel means axis of rotation for transmitting forward thrust to said cutting wheel means in a central thrusting state or a shield thrusting state of operation and for transmitting prying torque to said cutting wheel means in a prying state of operation;
• central body means for supporting said central thrust rod means in extendable and retractable relationship therein;
• central thrust generating means operably associated with said central body means for extending and retracting said central thrust rod means from said central body means;
• extendable and retractable sidewall engaging means mounted on said central body means for selectively engaging opposite portions of the tunnel peripheral sidewall for preventing relative movement of said central body means with respect to the tunnel sidewall in a central thrusting state of operation and for selectively radially shifting said body means relative the tunnel longitudinal axis for transmitting prying torque to said cutting wheel means through said central thrust rod means in a prying state of operation;
• central body support means for supporting said central body on the tunnel sidewall;
• annular shield means operably mounted on said central thrust rod means for shielding a portion of the machine from collapsing tunnel sidewall material;
• extendable and retractable shield thrust means operably associated with said shield means for coacting with the tunnel lining structure for selectively applying forward thrust to said cutting wheel means through said central thrust rod means during a shield thrusting state of operation;
• muck removal means for removing material cut by said cutting wheel means at the tunnel face to a rearward position within the tunnel;
• and
• control means for selectively operating various machine components.