High-efficiency blasting method for multi-stage ultra-deep holes with double-headed plugs and mud plugging for full-section soft rock tunnels

Abstract

The invention discloses a high-efficiency blasting method for tunnel soft rock full-section multi-stage ultra-deep hole double-head gun plug mud plugging, which relates to the technical field of tunnel blasting. High-efficiency blasting method with head plug + clay gun mud plugging; among them, No. 2 rock emulsion explosive is used for the explosive, non-electric millisecond detonator is used for the detonator, and nonel tubes are connected in series and parallel for the detonation network; holes are drilled with a pneumatic rock drill; blast hole layout : Cutting eye, inner ring eye, peripheral eye and bottom plate eye are all multiple, charge structure: cutting eye is continuously charged, peripheral eye is charged at intervals, inner ring eye and bottom plate eye are continuously charged, cut eye, Peripheral holes, inner ring holes and floor holes are all sealed with gun plugs + gun mud + gun plugs; the blasting footage is 3.9-4.1m, and the surrounding rocks are sealed by initial spraying of concrete after the ballasting. The invention overcomes the defects of poor blasting effect, low blasting efficiency and poor safety in the prior art, and can improve blasting effect, blasting efficiency and 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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