A shaft enlargement arrangement for a boring system is provided, the shaft enlargement arrangement comprising a hollow column proximate a lower end of the boring system; a first cutter head that is rotatably fitted to the hollow column, with first drive means being provided to rotate the first cutter head relative to the hollow column so as to bore downwardly a hole having a diameter corresponding substantially to the diameter of the first cutter head; and a boring head arrangement fitted to an operatively lower end of the column, the boring head arrangement terminating in a second cutter head to bore a leading hole as the boring system proceeds to bore downwardly. In an embodiment, the first cutter head comprises a support body carrying a winged arrangement, the support body being rotatably fitted to the column, the winged arrangement comprising a plurality of wings extending from the support body, each wing being fitted with, or comprising, a plurality of first cutter elements.

A shaft enlargement arrangement for a boring system is provided, the shaft enlargement arrangement comprising a hollow column proximate a lower end of the boring system; a first cutter head that is rotatably fitted to the hollow column, with first drive means being provided to rotate the first cutter head relative to the hollow column so as to bore downwardly a hole having a diameter corresponding substantially to the diameter of the first cutter head; and a boring head arrangement fitted to an operatively lower end of the column, the boring head arrangement terminating in a second cutter head to bore a leading hole as the boring system proceeds to bore downwardly. In an embodiment, the first cutter head comprises a support body carrying a winged arrangement, the support body being rotatably fitted to the column, the winged arrangement comprising a plurality of wings extending from the support body, each wing being fitted with, or comprising, a plurality of first cutter elements.

A shaft enlargement arrangement for a boring system is provided, the shaft enlargement arrangement comprising a hollow column proximate a lower end of the boring system; a first cutter head that is rotatably fitted to the hollow column, with first drive means being provided to rotate the first cutter head relative to the hollow column so as to bore downwardly a hole having a diameter corresponding substantially to the diameter of the first cutter head; and a boring head arrangement fitted to an operatively lower end of the column, the boring head arrangement terminating in a second cutter head to bore a leading hole as the boring system proceeds to bore downwardly. In an embodiment, the first cutter head comprises a support body carrying a winged arrangement, the support body being rotatably fitted to the column, the winged arrangement comprising a plurality of wings extending from the support body, each wing being fitted with, or comprising, a plurality of first cutter elements.

A top-down sequential-building construction method for deep and large vertical shaft cavern groups is provided. The construction method includes the following steps. A preparation is made for a construction. A vertical shaft locking beam is constructed. A vertical shaft is constructed. A post-construction maintenance is performed. The vertical shaft is constructed through a staged construction, which includes the following steps: S1, constructing from a vertical shaft surface to a contact air channel elevation; S2, constructing a contact air channel; S3, constructing from the contact air channel elevation to a vertical shaft bottom. Both constructing from the vertical shaft surface to the contact air channel elevation and from the contact air channel elevation to the vertical shaft bottom include constructing a lining structure from bottom to top.

A top-down sequential-building construction method for deep and large vertical shaft cavern groups is provided. The construction method includes the following steps. A preparation is made for a construction. A vertical shaft locking beam is constructed. A vertical shaft is constructed. A post-construction maintenance is performed. The vertical shaft is constructed through a staged construction, which includes the following steps: S1, constructing from a vertical shaft surface to a contact air channel elevation; S2, constructing a contact air channel; S3, constructing from the contact air channel elevation to a vertical shaft bottom. Both constructing from the vertical shaft surface to the contact air channel elevation and from the contact air channel elevation to the vertical shaft bottom include constructing a lining structure from bottom to top.