Patent ID: 7740417

Claim:
A construction method for installing underground pipes for high-tension cables by using a trough having a U shape and including a space section and a coupling groove formed at one side end of the trough, the method comprising the steps of: forming an excavation trench by excavating a ground to install the trough in the excavation trench, in which inclined surfaces are formed at both sides of the excavation trench at a predetermined inclination angle and a width of a bottom of the excavation trench is identical to a width of the trough; installing the trough on the bottom of the excavation trench by coupling a plurality of troughs through the coupling groove; pouring a predetermined amount of sand into the space section formed in the trough, placing the underground pipes, which receive the high-tension cables therein, on the sand at a predetermined interval, and pouring again the sand onto the underground pipes while flattening a top of the sand, thereby burying the underground pipes in the sand; filling a gap formed between an outer surface of the trough and a sidewall of the excavation trench using a mixture of sand and gravel until a height of the mixture is level with a height of the trough; forming an upper protecting member on a top of the trough by using concrete; filling a mixing layer over the upper protecting member, wherein the mixing layer comprises a material that is different from (a) the sand within the space section of the trough, and (b) the mixture of sand and gravel within the gap; and performing surface treatment by coating road pavement materials over the mixing layer.