| In the fields of coal,metals,non-metals,and infrastructure construction,mixed-emulsion explosives are being used more and more widely.However,at present,the formulation of mixed emulsified explosives used in most domestic mine blasting is relatively simple,and the explosive formula cannot be adjusted in time according to the rock properties of the blasting site,resulting in a mismatch between the performance of the explosive and the rock properties,and the occurrence of excessive or small blasting blocks.Causes explosive energy waste or poor blasting effect.Due to the diversity of geological conditions at the site of blasting operations,higher requirements are also placed on the diversity of explosive formulations.The thesis is based on the actual situation that the rock performance of each step of Beskuduk open-pit coal mine is quite different.It takes full advantage of the flexibility of the on-site mixed emulsion explosive formula and can be adjusted in time for the rock properties of different explosion areas.Blasting effect.Rock mechanics parameters were obtained through mechanical experiments on different flat rock samples in the mining area.A BP neural network was used to construct a prediction model for matching rock impedance with explosive impedance.The model was used to predict explosive impedance matching with rock impedance,and numerical simulation was used to analyze the matching.The effect is to design a mixed emulsified explosive formula with different explosive resistances and conduct field tests.The following progress has been made:(1)Acoustic wave detection is performed on rock bodies with different flat plates and rock samples are taken for mechanical experiments.Acoustic testing of large flat plates(1264 flat plate,1228 flat plate,1180 flat plate)that are prone to occur in the mining area found that the longitudinal wave velocity of the 1264 flat plate decayed the fastest,indicating that the 1264 flat plate rock mass is more developed and has more cracks;Through the mechanical experimental analysis of rock samples,to obtain the tensile strength,compressive strength,rock density,elastic modulus,Poisson’s ratio and other parameters of different flat rock;(2)The BP neural network is used to establish a prediction model that matches the impedance of the explosive wave and the impedance of the rock,collects engineering practice data and uses12 of them as training samples and 3 of them as test samples.Take the bulk density,compressive strength,tensile strength,elastic modulus,rock longitudinal wave velocity,joint spacing,large block rate,bedrock rate,blasting average block size,forward impact,backward impact,step height,and hole distance as models Input parameters,with the blasting speed,blast pressure,blasting heat,blasting capacity,intensity,hole depth,hole distance,row distance,chassis resistance line,explosive unit consumption as the output parameters.The comparison of the neural network model and the three sets of test samples after simulation found that the errors were all less than 10%,indicating that the neural network model can be applied to engineering practice;(3)Use the prediction model to predict the impedance of explosives matching the rock impedance of 1264,1228,and 1180 flats in the mining area,and use ANSYS/LS-DYNA software to analyze the matching effect of the predicted explosive impedance and rock impedance.The results show that:the closer the impedance of the explosive and the impedance of the rock,the greater the peak pressure on the wall of the blast hole;(4)Based on the currently used mixed-emulsion explosive formula in Xinjiang Bie Mine,the mixed-emulsion explosive formula with smaller rock impedance matching coefficient is designed for the rock properties of the 1264 flat plate,1228 flat plate,and 1180 flat plate.According to the characteristics of 1264 flat disk with more developed cracks,the coefficient of matching the impedance of the explosive with the rock impedance is improved by optimizing the aqueous phase formula;for the 1228 flat plate and 1180 flat plate,the foaming effect is improved by optimizing the foaming agent formula to achieve the reduction The purpose of the matching coefficient of rock impedance and explosive impedance;(5)The matching coefficients of the two sets of explosives and rock impedance designed by the 1264 flat plate are:the matching coefficient of the new formula 1 is 1.827,the matching coefficient of the new formula 2 is 1.698;the matching coefficient of the current mixed ammonium explosive is 3.144,indicating The impedance of the newly designed formula is closer to the impedance of the rock and the blasting effect is better;through the optimization of the foaming formula for the 1228 flat plate and the 1180 flat plate,the bulk rate is reduced from 6.8%to 5.3%;the unit consumption is reduced from 0.47kg/m~3to 0.44 kg/m~3;shows that by optimizing the formulation of the blowing agent,the matching coefficient between the impedance of the explosive and the impedance of the rock can be reduced. |
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