Tunnel boring machine for excavating semicircular-arched tunnels

A method of boring a tunnel having a semicircular-arched profile, the method comprising:

• providing a tunnel boring machine, having:
• a main support beam;
• a main cutterhead assembly rotatably coupled to a front end of a cutterhead support slidable with respect to the main support beam, wherein the main cutterhead assembly is configured to rotate with respect to the cutterhead support about a primary axis that is aligned with a centerline of a semicircular portion of the tunnel;
• a plurality of gripper assemblies located rearward of the main cutterhead assembly, the gripper assemblies being configured to selectively impart axial movement to the main cutterhead assembly;
• a pair of secondary cutterhead assemblies slidably mounted to and disposed on opposite sides of the main support beam, wherein each of the pair of secondary cutterhead assemblies is operably coupled to a drive system configured to rotate the secondary cutterhead assemblies about a secondary axis perpendicular to the primary axis;
• and
• at least one thrust cylinder configured to urge the pair of secondary cutterhead assemblies forwardly with respect to the main support beam independently of the main cutterhead assembly;
• positioning the gripper assemblies in an extended position wherein the gripper assemblies engage a tunnel wall of the tunnel to impart axial movement to the main cutterhead assembly and to react to boring forces of the tunnel boring machine;
• excavating a circular main cutterhead boring area of the tunnel by rotating and simultaneously thrusting the main cutterhead assembly into a tunneling substrate;
• excavating lower side portions of the tunnel by rotating and simultaneously thrusting the secondary cutterhead assemblies into the tunneling substrate;
• collecting primary muck created by the main cutterhead assembly during excavation and transporting the primary muck rearward with a backup conveyor extending along the main support beam;
• collecting secondary muck created by the secondary cutterhead assemblies during excavation and transporting the secondary muck rearward with peripheral conveyors positioned adjacent to the secondary cutterhead assemblies;
• and
• depositing the secondary muck on the peripheral conveyors to a common dump station above the backup conveyor such that the secondary muck combines with the primary muck for removal from the tunnel.

A tunnel boring machine for boring a semicircular-arched tunnel having a tunnel wall, the tunnel boring machine comprising:

• a main support beam;
• a main cutterhead assembly rotatably coupled to a front end of a cutterhead support slidable with respect to the main support beam, wherein the main cutterhead assembly is configured to rotate with respect to the cutterhead support about a primary axis that is aligned with a centerline of a semicircular portion of the tunnel;
• a plurality of gripper assemblies located rearward of the main cutterhead assembly, the gripper assemblies being configured to move between:
• a retracted position in which the gripper assemblies do not engage the tunnel wall;
• and
• an extended position wherein the gripper assemblies engage the tunnel wall to impart axial movement to the main cutterhead assembly and to react to boring forces of the tunnel boring machine;
• a pair of secondary cutterhead assemblies slidably mounted to and disposed on opposite sides of the main support beam, wherein each of the pair of secondary cutterhead assemblies has a carrier operably coupled to a drive system configured to rotate the secondary cutterhead assemblies about a secondary axis perpendicular to the primary axis;
• at least one thrust cylinder configured to urge the pair of secondary cutterhead assemblies forwardly with respect to the main support beam independently of the main cutterhead assembly;
• a backup conveyor configured to collect primary muck created by the main cutterhead assembly during use and transport the primary muck rearwardly for removal from the tunnel;
• and
• a pair of peripheral conveyors each mounted adjacent to one of the pair of secondary cutterhead assemblies, wherein the peripheral conveyors are configured to collect secondary muck created by the secondary cutterhead assemblies during use and deliver the secondary muck to a common dump station above the backup conveyor such that the secondary muck combines with the primary muck for removal from the tunnel.

A method of boring a tunnel having a semicircular-arched profile with a tunnel boring machine, having:

• a main support beam;
• a main cutterhead assembly rotatably coupled to a front end of a cutterhead support slidable with respect to the main support beam, wherein the main cutterhead assembly is configured to rotate with respect to the cutterhead support about a primary axis that is aligned with a centerline of a semicircular portion of the tunnel;
• a plurality of gripper assemblies located rearward of the main cutterhead assembly, the gripper assemblies being configured to move between:
• a retracted position in which the gripper assemblies do not engage a tunnel wall of the tunnel;
• and
• an extended position wherein the gripper assemblies engage the tunnel wall to impart axial movement to the main cutterhead assembly and to react to boring forces of the tunnel boring machine;
• a pair of secondary cutterhead assemblies slidably mounted to and disposed on opposite sides of the main support beam, wherein each of the pair of secondary cutterhead assemblies has a carrier operably coupled to a drive system configured to rotate the secondary cutterhead assemblies about a secondary axis perpendicular to the primary axis;
• and
• at least one thrust cylinder configured to urge the pair of secondary cutterhead assemblies forwardly with respect to the main support beam independently of the main cutterhead assembly,
• the method comprising:
• positioning the gripper assemblies in the extended position wherein the gripper assemblies engage the tunnel wall to impart axial movement to the main cutterhead assembly and to react to boring forces of the tunnel boring machine;
• excavating a circular main cutterhead boring area of the tunnel by rotating and simultaneously thrusting the main cutterhead assembly into a tunneling substrate;
• collecting primary muck created by the main cutterhead assembly during excavation and transporting the primary muck rearward with a backup conveyor extending along the main support beam;
• excavating lower side portions of the tunnel by rotating and simultaneously thrusting the secondary cutterhead assemblies into the tunneling substrate;
• collecting secondary muck created by the secondary cutterhead assemblies during excavation and transporting the secondary muck rearward with peripheral conveyors positioned adjacent to the secondary cutterhead assemblies;
• and
• depositing the secondary muck on the peripheral conveyors, wherein the peripheral conveyors are configured to convey the secondary muck to a common dump station above the backup conveyor such that the secondary muck combines with the primary muck for removal from the tunnel.