Techniques and mechanisms to form a reinforcement structure including dirt processed during drilling of a tunnel. In an embodiment, a device includes a drill head to drill an underground tunnel, where a housing of the device takes in dirt produced by such drilling. A mixer and other components of the device variously condition the dirt to produce a casing material that is subsequently provided to a compactor of the device. The compactor extrudes the casing material through a die. The extruded casing material is eliminated from the device to form a reinforcement structure at one or more sides of the tunnel. In another embodiment, a fiber optic cable is paid out from the device into the tunnel during the drilling, or is pulled into the tunnel by the device during the drilling.

A tunnel boring machine includes: a shield body; a cutterhead assembly, a first drive mechanism; a second drive mechanism; and a third dive mechanism. The cutterhead assembly includes a main cutterhead and a plurality of auxiliary cutterheads. The main cutterhead is rotatably arranged at a front side of the shield body and defines a soil chamber between the main cutterhead and the shield body, and is movable along an up-down direction. The plurality of auxiliary cutterheads are rotatably arranged in the soil chamber, and adjacent to a bottom of the shield body and arranged at left and right sides of a vertical central line of the main cutterhead. A rotation diameter of the main cutterhead is greater than a rotation diameter of the auxiliary cutterhead, and the rotation diameter of the main cutterhead is the same as a maximum width of the shield body.

A tunnel boring machine includes: a shield body; a cutterhead assembly, a first drive mechanism; a second drive mechanism; and a third dive mechanism The cutterhead assembly includes a main cutterhead and a plurality of auxiliary cutterheads. The main cutterhead is rotatably arranged at a front side of the shield body and defines a soil chamber between the main cutterhead and the shield body, and is movable along an up-down direction. The plurality of auxiliary cutterheads are rotatably arranged in the soil chamber, and adjacent to a bottom of the shield body and arranged at left and right sides of a vertical central line of the main cutterhead. A rotation diameter of the main cutterhead is greater than a rotation diameter of the auxiliary cutterhead, and the rotation diameter of the main cutterhead is the same as a maximum width of the shield body.