| 摘要 |
PROBLEM TO BE SOLVED: To provide a drilling method suited to the drilling of an earthing hole for an electric apparatus and to provide a drilling rig suited in use for earthing work. SOLUTION: When the earthing hole is drilled by the drilling rig, an auxiliary electrode is installed near a drilling position, a drilling rod itself is connected to an earthing resistance meter as the earthing electrode, and drilling is performed till the earthing resistance reaching a prescribed value or less. During the drilling, slurry formed by dissolving slaked lime in water is introduced in the hole. When completing the drilling, carbon dioxide is blown into the hole to solidify the slurry. This drilling rig is provided with a driving device for a rock drill in the upper part of a guide cell vertically movably mounted with the rock drill, a suspension device for suspending to a crane, a foot pad fixing the guide cell to the ground in the lower end of the guide cell, and a fixing device fixing the guide cell to a column such as a pole in the rear surface side respectively. COPYRIGHT: (C)2004,JPO
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