A blasting method for directional fracture and slotting of mixed wedge-shaped kerf charges in hard rock roadways

Abstract

The invention discloses a medium-length hole mixed wedge cut blasting method capable of realizing directed fracture using a cutting cartridge bag for a solid rock roadway. According to the method disclosed by the invention, 3-4 pairs of vertical wedge cutting holes are arranged at lower half places of an excavating working face; the vertical wedge cutting holes comprise mirror-arranged primary cutting holes and secondary cutting holes that are arranged at the two sides of the primary cutting holes; the primary cutting holes comprise three blast holes that are arranged side by side; the secondary cutting holes comprise four blast holes that are arranged side by side; 1-2 straight holes are formed in the middle portion of each primary cutting hole; a distance between every two adjacent blast holes in the primary cutting holes is 800-1000mm. According to the method disclosed by the invention, the advantage of directed fracture blasting of the cutting cartridge bag is fully utilized, so that an orifice distance and a row distance of the primary cutting holes are increased, the number of blasting holes is reduced, explosive unit consumption is decreased, disturbance damage to the roadway surrounding rocks by cut blasting is effectively controlled, the original strength and stability of the roadway surrounding rocks are guaranteed, and favourable conditions are provided for repairing and maintenance works during later roadway support and operation progresses.

Description

Technical field [0001] The invention relates to a medium and deep hole wedge-shaped cut blasting method for roadways, in particular to a directional fracture cut blasting method for medium and deep holes in hard rock (f=10-16) roadways with mixed wedge-shaped slitting cartridges. Background technique [0002] my country is rich in coal resources, widely distributed, and mainly underground mining. Key state-owned coal mines only have rock tunnel excavation works above 2000Km each year. Drilling and blasting is still the first choice for tunnel excavation construction. Medium-deep hole blasting can reduce auxiliary work time, increase single-cycle footage, save a lot of blasting equipment, accelerate the speed of roadway blasting and obtain better economic benefits, and is considered to be one of the most effective technical means to accelerate the speed of excavation. The development direction of tunnel blasting. [0003] At the same time, in tunnel blasting, cut blasting has alway...

AI Technical Summary

Problems solved by technology

[0005] However, due to the difficulty of roadway blasting in hard rock (f=10-16), especially the large consumption of explosives in cutting blasting, the disturbance and damage to the surrounding rock of the roadway are large, and the maintenance and repair costs in the roadway operation stage are high; The quantity is large, and the drilling workload is large; and the utilization rate of blastholes is generally low, which can only reach about 50%; the rate of large pieces of rock bursting is high, the rate of excessively broken rock pieces is also high, and the efficiency of rock loading and transportation is low; thus making The blasting and excavation cycle time of the entire roadway is prolonged, which seriously affects the construction progress

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