Research On Raise Excavation Technology By Long Hole Blasting Considering Hole Deviation

Blasting hole is affected by many factors in the drilling process of sky shaft excavation,such as joint cracks,drill bit drill pipe quality,operator technology,etc.the cannon hole is deflected,which changes the original compensation space and the size of the resistance line,resulting in“recycled rock” due to the small spacing between the holes during blasting or "squeezing" due to insufficient compensation space,resulting in the failure of blasting into a well or the effect of the well is not satisfactory.At present,most of the blasting well designs does not consider the influence of hole deviation,so this paper studies the influence of blasting into wells.The mechanism of borehole deviation is analyzed,and the factors affecting borehole deviation are found.Combined with the measured data of mine borehole,the characteristics of borehole deviation are analyzed.With the help of numerical simulation,the borehole layout optimization of straight hole cutting blasting well and the influence of borehole deviation on the layered height of porous spherical charge blasting well are studied.Finally,the field test is used to demonstrate the influence mechanism of borehole deviation on blasting well completion,which provides theoretical basis and scientific basis for the promotion and application of deep hole blasting well completion technology.The main research contents and conclusions of this paper are as follows :(1)By analyzing the mechanism of borehole deviation,the principle of borehole deviation is studied,it is confirmed that the borehole deviation is affected by many factors,among which the most important factors are the flatness of the roof and floor,the positioning error of the opening,the accuracy of the equipment,the operation level,the property and management of the rock layer.By analyzing the measured data of the mine,it is found that the deviation rate of large aperture is lower than that of small aperture in the same stope,and the hole deviation rate of the same aperture in the stope obeys normal distribution.(2)The calculation of well completion parameters of straight-hole cut blasting without considering borehole deviation was analyzed,and then the influence of borehole deviation rate on rock breaking effect of straight-hole cut blasting was analyzed by numerical simulation.The change of rock stress during rock breaking was described by adding stress monitoring points.According to the simulation results,the borehole deviation rate is introduced to modify the existing calculation formula of blasting well completion parameters,and the calculation methods of empty hole diameter and hole spacing under different borehole deviation rates are given.On this basis,the anti-deviation ability of different cutting forms is deduced.(3)The three-dimensional numerical simulation of blasting well completion with porous spherical charge was carried out.By simulating the deviation of hole bottom in actual production,the blasting effects of different layered heights under different deviation rates were simulated.The results show that the blasting effect is greatly affected by the deviation when the deviation is large.At this time,the blasting layer height needs to be reduced to improve the quality of blasting well completion.When the deviation is small,the blasting effect is less affected by the deviation.At this time,the blasting stratification height can be improved and the efficiency of well formation can be improved.(4)A new cutting mode,hybrid cutting,was proposed.Three cutting modes were designed in the sky shaft with the average deviation rate of0.97 %.The bottom adopted the porous spherical charge mode,the middle adopted the hybrid cutting mode,and the upper adopted the straight hole cutting mode.The field test was carried out.The porous spherical charge mode compared the blasting completion of 2.2 m and 2.5 m layers.The blasting completion of 5 m layers was set in the hybrid cutting mode,and the sky shaft of 15.2 m was blasted once in the straight hole cutting blasting completion.The results show that the blasting effect of low stratification in porous spherical cartridge is better.When the hole deviation rate is small and meets the straight hole cutting,the efficiency can be greatly improved.When the hole deviation is between the two,the mixed mode is better and more efficient.The optimization method is given when the deviation rate is large.