Grey Relation Analysis Of Influence Factors With Blasting Effect

The blasting effects contain the fragmentation of rock after blasting, loose of blasting pile and accumulated shape, the conditions of bottoms and hard walls, the negative effects of blasting and technical economic benefit. The quality of blasting effects had an direct influence on the efficiency of shoveling, transporting and initial fracturing and the other process of mining. It was an important subject that attracted attention of blasting engineers and mine owners.Rock mass blasting is a complicated process affected by mutual interaction of many factors. The fragment-size distribution predicting model and the crucial factors that affect blasting results were studied in the paper, the relationship of all factors was analyzed as well. Based on the grey relevancy theory, according to the sample survey of the fragment-size distribution taken in a large surface mine, the primary and secondary relationship of factors that affect the blasting results was studied. From the analysis, the major factor that affect the fragment-size could be modified more accurately and directly to improve the blasting parameters, lower the boulder yield and finally reduce the mining and blasting costs.According to actual experience of the surface mine, the rock mechanical properties, explosive performance parameters and mesh parameters were chosen as related variables. The evaluate indexes of blasting effects(y1-average fragment; y2-boulder yield; y3-kickahead; y4-kickback; y5-lifting height) were taken as system characteristic variables. The results from grey relational analysis were:(1) The grey absolute relation grade of powder charge was the largest in all of the six group experiments, which was the major factor that affect fragment-size distribution. (2) The explosion heat affected more marked on blasting effect than VOD(velocity of detonating), so the larger explosion heat explosive should be firstly considered to choose. (3) The tensile strength of rock affected more marked on the blasting effects than the compressive strength. Thus, the tensile failure was the main failure type in rock blasting. (4) The primary and secondary relationship would change with different regions and different blasting conditions when all factors that affect fragment-size was analyzed with grey relevancy theory. Therefore, the analysis should collect the sample data from specific rock blasting, and then predict and analyze the factors that affected blasting quality to achieve the desired purpose.