Dynamic Analysis And Optimization Study Of Deep Hole Cutting Blasting For Roadway Drivage

Tunnel blasting was an important part of mine production operation.At present,drilling and blasting method was adopted for underground mine tunneling construction.With the improvement of mining mechanization,advanced drilling tools were applied to mines.The construction of mine tunneling blasting has developed from the former medium deep hole blasting to deep hole blasting.The average depth of borehole was about 3.65 m,Compared to before the maximum depth of 3m,borehole has greatly improved.Found in the blasting process,without changing the way of charging,the way of cutting and the way of blasting,only increased the length of the hole,It did not increase the footage of the single cycle and the effect of blasting.In order to study the increase of blasthole depth and The dose of explosive.But the blasting effect(Drift forming,single cycle footage,rate of blasting etc)did not increase significantly.Three aspects(theoretical analysis,numerical simulation,field investigation and experiment)were studied.Firstly,started with the theory,In the process of explosion,The effect of different size ratio on blasting was discussed.rock was broken by the stress wave in the first stage,in damage and destruction of rock structure.Then,the quasi-static pressure of the detonation gas acted on the damaged surface of the medium and its fracture.Further promote the expansion and coalescence of fractures.cutting area in deep hole blasting in rock roadway excavation in the one free surface state and rock clamping effect is severe,rock crushed was no compensation sufficient space,setting the compensation space reasonable in cutting area was to optimize the blasting effect.Secondly,the cutting method of cutting blasting in deep hole driving is simulated through the finite element simulation software ANSYS/LSDYNA,numerical models of two empty holes and four empty holes were established.The stress and velocity time history curves were analyzed by means of corresponding stress nephogram,Simulation results showed that The compensation space was the main reason for the unsatisfactory cutting effect.When the number of empty hole was 2,the cutting effect was the worst,the residual hole more and large block rate was high,when he number of empty hole was 4,low consumption,large block rate was high and large residual hole was less.blasting effect is the best.and cavity forming was good.Finally,a cutting scheme with the number of empty hole is 4 finally established.Thirdly,combined with theoretical analysis and numerical simulation,The empty hole linear cutting scheme was used to carry out field blasting experiment.The experimental results showed that with the increase of the number of empty holes(the number of empty holes is generally 4).The blasting effect has been greatly improved,When the number of empty holes was 4,blasting footage and the block were the best.the residual hole was less.When the number of empty hole was 2,hole remains as high as 60 cm,high rate of blasting,the blasting effect was the worst.Finally,theoretical analysis,numerical simulation and experimental investigation were conducted.The conclusion is that the reasonable number of empty hole is 4 in deep hole blasting.It is not only beneficial to improve the use of explosive energy rate and easy to construct and operate,but also to optimize the blasting fragmentation.