| In the national infrastructure construction vigorously promote the development of today,in many need a lot of earthwork excavation projects,drilling and blasting method is widely used in mining,highway,railway,tunnels and other large-scale infrastructure construction projects,highlights its irreplaceable superiority,and with the rapid development of social e conomy is more and more show its important role.The key to adopt the drilling and blasting method lies in the layout of the cutting hole and the choice of the blasting initiation mode,and the ultimate purpose is to save the construction cost,improve the economic benefit and construction efficiency.Reasonable parameter design and construction method in drilling and blasting method can effectively reduce the construction cost and improve the construction efficiency.Blasting excavation should not only meet the requirements of rock mass crushing,but also reduce the damage of the surrounding rock as far as possible.Therefore,the reasonable blasting method can make the energy fully and evenly act on the rock mass in the blasting construction process,and a void the production of large gangue,which is of great significance to the rapid excavation of rock roadway.This paper takes the blasting project of Shanxi Yangmei Group,and the main research contents are as follows:With ANSYS/LS-DYNA numerical simulation analysis software to establish blasting model,research using different way of blasting damage between two hole area and hole bottom area and effective stress transmission and distribution,found that the combination of the effective stress distribution in the rock mass,different way will affect the propagation direction of detonation wave,and affect the superposition of explosion stress wave.Therefore,it is necessary to adjust different starting points to make full use of the rock.Through the comparison test,it can be found that when the bottom bursts,at the same time,the effective stress increases and then decreases;when the middle of the hole increases from the middle to the bottom,when the time,the stress distribution of the explosion occurs more uniform,which is easy to lead to the residual root after the explosion.The comparison shows that the method of simultaneous explosion initiation at the middle and bottom can more effectively use the explosion stress wave,which can be used to guid e the field test.To further analyze the impact of blasting mode on the surrounding rock damage,using organic glass as a kind of rock medium,the double-hole blasting test was designed,and combining with the fractal dimension was used to analyze the difference of explosion damage.The results show that the fractal dimension of the two blasting holes is 1.424,1.438,1.254,1.544,1529,and1.296are1.7112,0.719,0.627,0.772,0.7645,0.648,respectively.The fractal dimension fitting result of the hole bottom shows that the fractal dimension of the burst crack in the hole bottom area is 1.495,1.553,1.209,1.475,1.479,and1.356,respectively.The corresponding damage level is 0.7475,0.7765,0.6045,0.7375,0.7395,and 0.678,respectively.Through comparati ve analysis,it is found that the bottom of the hole and the key parts can better achieve the effect of destroying the rock rupture.According to the model test and numerical calculation results,the site blasting construction is guided.After adopting the optimized blasting scheme,small fragments are produced,and the blasting reduces the large gangue,reduces the support time,and ensures the construction quality,thus improving the working efficiency of unit time. |
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