The present invention relates to a method and apparatus for supporting the wall of an upwardly excavated shaft without requiring workmen to approach the wall to be supported or shielded.
Heretofore, the process for supporting the wall of an upwardly excavated shaft generally included scaffolding in the shaft, delivering frame members up into the shaft one after another and then manually putting the frame together to complete the shielding. Such a manner of shielding naturally required the workmen to carry out their labor at the risk of falling, and further involved the danger of the destruction of the roof and the side wall or vertical wall of the shaft, as well as unsanitary conditions due to the dusty and stagnant environment.
In order to eliminate the above mentioned defects of the old techniques, the inventors developed, as disclosed in Japanese Patent Application No. 37542/1976, corresponding to U.S. application Ser. No. 895,103, a system for carrying out upwardly directed full face cutting accompanied by shielding of the wall, which comprises the steps of upwardly cutting a predetermined length of a shaft by a rotary bit and supporting the corresponding length of thus shaped side wall by means of at least one cylindrical frame section, whereby each of such two steps are carried out repeatedly. While such system brought about remarkable improvements in shielding or supporting the wall of an upwardly directed shaft without requiring workmen to enter into the shaft, the inventors found that the shielding of the wall including the side wall or vertical wall and the roof can be more beneficially made by providing a novel side wall support frame and a roof support frame each of which will be explained in detail hereinafter.