Casing installation method for prevent collapse of fractured zone

摘要

The present invention relates to a casing construction method for preventing collapse of a crusher, and when a crusher appears in the rock layer drilling step of drilling a borehole of a preset diameter in the rock layer and the rock layer drilling step, the crusher is drilled larger than the diameter of the borehole with an excavation bit After mounting an expansion casing with a diameter expandable on the outer surface of the packer, the diameter of which is variable by the inflow and outflow of the crusher and the expansion casing arrangement step of placing the expansion casing in a position corresponding to the crusher, and the diameter of the packer Expansion includes an expansion casing fixing step of fixing the outer surface of the expansion casing in close contact with the inner circumferential surface of the crusher and a packer lifting step of reducing the diameter of the packer and lifting the packer, repeating the above steps until the borehole drilling is complete characterized by performing. According to the present invention as described above, as the crushing zone in the rock layer is more reliably prevented from collapsing, the jamming phenomenon of the drilling rod due to the collapse of the rock pieces separated from the crushing zone occurs or the burial accident of the bore tester performed during drilling can be prevented in advance. In addition, since the present invention does not use the cement grouting method, a separate time for curing the cement is not required, and thus the construction period is significantly shortened, so that the construction cost can be greatly reduced. In addition, since the work of re-drilling the cured cement grouting is not performed, the problem that the re-borehole deviates from the original borehole and the overall borehole is displaced does not occur.