Tunnel soft rock full-section multi-stage ultra-deep hole double-end plug and stemming plugging high-efficiency blasting method

Abstract

The invention discloses a tunnel soft rock full-section multi-stage ultra-deep hole double-end plug and stemming plugging high-efficiency blasting method, and relates to the technical field of tunnelblasting. The full-section multi-stage same-depth inverted square-frustum-shaped ultra-deep hole double-end plug and clay stemming high-efficiency blasting method is adopted, wherein a No. 2 rock emulsion explosive is used as an explosive, a non-electric millisecond detonator is used as a detonator, and a detonating network is formed by serial and parallel connection of detonating tubes; a pneumatic rock drill is used for drilling; a blast hole layout diagram is as follows: multiple cutting holes, inner ring holes, peripheral holes and bottom plate holes are arranged; a charging structure is formed in such a way that the cutting holes are continuously charged, the peripheral holes are charged at intervals, the inner ring holes and the bottom plate holes are continuously charged, and the cutting holes, the peripheral holes, the inner ring holes and the bottom plate holes are plugged each through a combined mode of a plug, stemming and a plug; and the blasting footage is 3.9-4.1m, and the surrounding rock is sealed by concrete primary spraying after slag discharge. The method overcomes the defects of poor blasting effect, low blasting efficiency and poor safety in the prior art, andcan improve the blasting effect, the blasting efficiency and the safety.

Description

technical field [0001] The invention relates to the technical field of tunnel blasting, in particular to a high-efficiency blasting method for tunnel soft rock full-section multi-stage ultra-deep hole double-headed plug mud plugging. Background technique [0002] The exit work area of ​​a double-track tunnel of a high-speed railway is designed as grade IV soft rock, and the excavated surrounding rock is revealed to be sandy and carbonaceous shale, with well-developed joints and fissures, well-developed fissure water, beaded leakage, and moderate self-stability. Next, the full-face drilling and blasting method is adopted for construction. [0003] (1) Using IVa2 support parameters: [0004] ① Advance support adopts φ42 small conduits, 4.5m in length, 3.0m in longitudinal spacing, 40 in each ring, and 0.5m in circumferential spacing. [0005] ② The initial support adopts shotcrete, steel mesh, anchor rod and I18 steel. [0006] Shotcrete: C25 concrete, 25cm thick for the ar...

AI Technical Summary

Problems solved by technology

[0019] ① Blast holes are blocked by blasting mud. Because the quality of blasting mud is difficult to guarantee, the blasting efficiency is low, about 70%, resulting in limited blasting footage, and the cycle footage is 3.2-3.5m

②Peripheral eye blasting effect is poor, over- and under-excavation is difficult to control, local over-excavation wastes spray anchor material, local under-excavation needs to be repaired, wastes process time, and disturbs the surrounding rock many times, resulting in block drop, high safety risk

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