HIGH-STRENGTH EARTH-WIRE UNDER-BRACING CONSTRUCTION METHOD USING CIRCULAR EARTH-WIRE UNDER-BRACING AND HYDRAULICALLY EXPANDABLE EXCAVATING SCREW

摘要

The present invention relates to a circular earth-wire under-bracing construction method for supporting and securing a utility pole when carrying out mechanised pole-installation work using the excavating screw of an auger crane. More particularly, the present invention is advantageous in: that the pullout resistance of the circular earth-wire under-bracing, which is laid underground, is improved by increasing the soil-resistance surface area thereof; that, as excavation is carried out in stages on the contact portion between an earth rod and a part for burying the circular earth-wire under-bracing, through the excavating screw which is automatically expanded by hydraulic pressure, the soil-resistance surface area of the circular earth-wire under-bracing in contact with infilled soil is increased due to the increased size of the earth-wire under-bracing, and the force supporting the utility pole through the earth rod is substantially improved, and thus a force which effectively supports the utility pole is maintained even when the weight of various forms of materials and equipment is increased due to the installation of large power lines and to an increase in the power distribution voltage in order to increase power supply capacity; that communications wires can be installed in parallel and a large amount of materials and equipment associated with power facilities can be added within existing lines, and thus integrated, heavy-loading power distribution lines can be provided and the aesthetic appearance of power facilities can be improved while at the same time the surface area of land they occupy is reduced; that high-strength earth-wire can be constructed using only a single earth-wire under-bracing, thereby obviating the need for any additional earth-wire construction; and that, by using an auxiliary excavation blade which is automatically expanded by hydraulic pressure, the construction method of the present invention allows fast and effective excavation of the contact portion between the earth rod and the part for burying the under-bracing and provides outstanding workability and economic advantages, and can replace conventional circular earth-wire under-bracing construction methods which use manually operated expansion apparatuses.