Patent ID: 8757731

Claim:
A method for boring a vertical shaft underground, the shaft having a shaft floor, said method comprising the following steps: providing a shaft boring machine having a cutterwheel rotatable about a horizontal axis and about a vertical axis intersecting the horizontal axis, wherein the vertical axis is a central vertical axis with respect to the circumferential wall of the shaft and rotation of the cutterwheel about the horizontal axis and about the vertical axis is configured to deepen the shaft; executing a first excavating cycle by the following steps: bracing the shaft boring machine against a circumferential wall of the shaft; rotating the cutterwheel solely about the horizontal axis to form a penetration trough extending over the total diameter of the shaft having a penetration depth deeper than the shaft floor; subsequently, rotating the cutterwheel concurrently about the horizontal axis and in a first direction about the vertical axis approximately 180° with the cutterwheel excavating material to extend the circumferential wall of the shaft and to form a first new shaft floor; and following the first excavating cycle, executing a second excavating cycle by the following steps: rotating the cutterwheel solely about the horizontal axis to form a penetration trough extending over the total diameter of the shaft having a penetration depth deeper than the first new shaft floor; subsequently, rotating the cutterwheel concurrently about the horizontal axis and in a second direction, opposite the first direction, about the vertical axis approximately 180° with the cutterwheel excavating material to extend the circumferential wall of the shaft and to form a second new shaft floor.