Experimental Research On The Charge Technology For Cross Strata Antireflective Deep-hole Pre-splitting Blasting

Deep hole pre-splitting blasting has been widely used in the national economic construction and resources mining, and charging technology is closely related to the blasting effect. With the rapid development of coal industry, the mining depth increasing, the permeability of coal seam is lower, the mining faced severe challenges. Deep low permeability gas coal mine, therefore, the researches on the mechanism of the anti-reflection of gas disaster in coal mine is still the important subject. In recent years, deep hole blasting technology is gradually applied in the coal seam anti-reflection and shaft uncovering coal and mining thick roof weakening in advance d, the research of charging technology which can improve the blasting effect was very important.Based on model test and the ultra dynamic strain test, according to the rock blasting theory and stress wave propagation theory, completed the coal charging, roof charging and coal-rock interface charging model experiment of blasting anti-reflection, at the same time the super dynamic strain test of coal-rock interface charging has been made. The experimental results show that:although coal charging can reach anti-reflection effect in the short term, but charging is difficult and fissure hold time is short, short extraction time. while the roof charging is convenient and can produce a large number of cracks, but less disturbance on the coal seam, the anti-reflection effect is not ideal. Coal-rock interface charging made full use of the rock drilling hole forming good characteristics, utmost ground to avoid the charge difficulties which caused by coal seam collapse; After blasting fracture developed in coal seam and rock, and in the roof of coal-rock interface layer with fissure network in rock fracture connectivity, form the three-dimensional network structure, extraction range is larger; Rock crack can compensate for coal seam in the sustain of the shortcoming of short time, make pure gas amount increases, extraction time is longer. Displacement and stress time is greater than the rock properties, this difference makes the stress wave in the process of transmission at the interface between coal and rock tensile compression, repeatedly waves effect for the good of the growth of crack growth in coal and rock.A deep hole pre-split blasting anti-reflection experiment has made in this paper, this paper expounds the coal-rock interface charging in deep hole pre-split blasting in the application of the anti-reflection layer. Application results show that after nearly a month after deep hole pre-splitting blasting, drilling field extraction from pure gas amount reached1.4times of blasting before, up to7.1times that of before blasting and2drilling field in continuous extraction from23days later still can reach5.8times before blasting. The above data shows that coal-rock interface containing medicine for deep hole pre-splitting blasting anti-reflection extraction effect has improved significantly. The charging mode make full use of the reflection and transmission of stress wave in layered rock mass energy transfer law of stress wave in coal-rock interface generates multiple reflective stretching, the blasting effect is superior to single in rock or coal seam, and generated in the interface and the coal and rock is advantageous to the gas discharge channel. Blasting of anti-reflection effect can be enhanced greatly, improve the security of the coal bed mining. Offers a new way to improve the blasting effect.