VIBRATION-FREE RAPID EXCAVATION METHOD USING PILOT TUNNEL IN LARGE-SCALE TUNNEL

摘要

The present invention relates to a method of gradually blasting a pilot tunnel base ground between a pilot tunnel and a prearranged main tunnel excavation surface by excavating a pilot tunnel, boring an elongated hole from the prearranged main tunnel excavation surface to the tunnel base ground, inserting a pre-support into the elongated hole, grouting the ground to reinforce the ground, and charging an empty hole formed when the pre-support is inserted into the pilot tunnel base ground from the pilot tunnel and the prearranged main tunnel excavation surface and a radial hole additionally formed with explosive powder. The method of gradually blasting a pilot tunnel base ground comprises the steps of: excavating a pilot tunnel to be spaced apart from a prearranged main tunnel excavation surface in order to insert the pre-support into the tunnel and excavate the tunnel; inserting and grouting a pre-support material by forming an elongated hole in the tunnel base passing the main excavation surface of the prearranged main tunnel from the pilot tunnel; boring a plurality of main tunnel holes in the excavation surface of the prearranged main tunnel in a vertical direction; boring a radial charging hole in the base ground of the pilot tunnel in the vertical direction of the tunnel; connecting gunpowder and detonators by groups of sections, charging the charging hole with the connected gunpowder and detonators and connecting gunpowder and detonators to cross sections of empty holes formed when the pre-support is inserted and charging the empty hole with the connected gunpowder and detonators; gradually blasting the charging holes from a blind end of the tunnel in the vertical direction of the tunnel; removing pumice stones of the excavated surface formed by the blasting; and taking out generated muck and additionally supporting the excavated surface.;COPYRIGHT KIPO 2018