A kind of blasting excavation method of hard rock tunnel

Abstract

The invention discloses a hard rock tunnel blasting excavation method. The hard rock tunnel blasting excavation method comprises the steps that blasting holes are drilled in the rock of a tunnel faceand include cut holes, auxiliary holes, peripheral holes, bottom holes and empty holes, and at least one empty hole is formed in the periphery of each cut hole; the blasting holes are cleaned; explosives are put into the cut holes, the auxiliary holes, the peripheral holes and the bottom holes; a front stemming section, a resisting part and a rear stemming section are put into the remaining part of each cut hole in sequence, the hole opening of each cut hole is tightly wedged by a wedge, branches are arranged on each resisting part, each resisting part is pushed into the corresponding cut holein the forward direction, and the interiors of the remaining parts of the auxiliary holes, the peripheral holes and the bottom holes are plugged by stemming sections; blasting cap leg wires of the explosives are connected, and ignition and blasting are conducted; after the blasting is accomplished, and residue removal is conducted on the blasted tunnel face; and the operation is repeated until hard rock tunnel blasting excavation is accomplished. The tunnel blasting cyclical footage can be increased, and the tunnel excavation speed can be increased.

Description

technical field [0001] The invention relates to the technical field of tunnel excavation, in particular to a blasting excavation method for hard rock tunnels. Background technique [0002] Tunnels are key and key projects in the construction of roads and railways. With the development of railway construction and the advancement of science and technology, tunnel excavation methods have been developed rapidly. The more commonly used excavation methods are drill and blast method, shield method and roadheader method. Because the drill and blast method has strong adaptability to geological conditions and low excavation cost, it is especially suitable for the construction of hard rock tunnels, broken rock tunnels and a large number of short tunnels. Therefore, the drill and blast method is still a commonly used tunnel excavation method at home and abroad. But the harder the rock, the more difficult and inefficient the tunnel construction. For example, for the blasting excavatio...

AI Technical Summary

Problems solved by technology

But the harder the rock, the more difficult and inefficient the tunnel construction

For example, for the blasting excavation of tunnels with rock firmness coefficient f=6~10 mainly composed of sandstone and slate, the cutting hole adopts the existing oblique-hole wedge-shaped cutting arrangement, while the hand-held rock drill can only drill 2.5m The blastholes below are rock hard, and the footage per shot is only 1.5-2.0m, and the monthly progress is only 40-60m. From the start of construction in September 2016 to October 25, 2018, more than half of the construction period has been completed, and only 17 % construction progress

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