| In recent years,with the increasing strength of China’s comprehensive national strength and the rapid development of science and technology,China’s investment in the field of infrastructure continues to increase,and the rapid development of highway construction.Due to China’s vast territory and ever-changing terrain,extra long highway tunnels continue to emerge.However,due to the long distance of extra long highway tunnels,it is particularly prominent to solve the ventilation problem.The construction of tunnel ventilation shaft can solve this problem well.At present,most of the domestic shaft construction is still based on drilling and blasting method.Because of its strong adaptability to engineering,it can be used in all kinds of rock mass in our country.The superiority of drilling and blasting method leads to the use of this method in shaft excavation construction for a long time in the future.How to speed up the shaft driving speed is the main factor to improve its economic benefits.Combined with the project of No.2 ventilation shaft of Tiantaishan tunnel in Qinling Mountains,this paper studies the optimal blasting parameters and rapid excavation of ventilation shaft by means of laboratory test,theoretical research,model test and field test.The main contents of this paper are summarized as follows(1)Through the tunnel from the qinling are green in the field of shaft construction of 2 # granite specimen under uniaxial compression,triaxial compression test,analyzes the various granite mechanics index,using the empirical formula method of indoor test results of processing,the rock mechanics parameters of the flower show post rock under uniaxial compression condition characterized by obvious brittleness,the deformation of rock under triaxial state characteristics of the plastic for blasting optimization,the blasting test laid a good foundation,provide the basis for the selection of parameters.It makes the optimization more close to the engineering practice and greatly improves the accuracy.(2)Based on shaft wall rock blasting fragmentation of the Split-Desktop4.0recognition method,defines the best piece for 300 mm below the 80% to 90% can greatly improve the efficiency of the gangue proposed global intelligent optimization method of blasting optimization hybrid algorithm,simulated annealing-gaussian process to get the best blasting optimization plan 323332,namely hole depth of 3.5 m,perforation of 35 cm in diameter,single hole charge 2.4 kg for the 800 mm hole spacing,hole Angle is 90,the minimum resistance line is 550 mm(3)In view of the optimized blasting scheme,the blasting vibration test of the air supply and exhaust shaft was carried out.The results of blasting vibration test show that the maximum blasting vibration velocity usually occurs when the cut hole is blasted during the tunnel ventilation shaft blasting construction.The vibration velocities of the measured points have significant differences in X,Y and Z directions.Among them,the vertical vibration velocity Vz has the greatest influence on the ventilation shaft,that is,the vibration velocity in this direction has the greatest influence on the support system.The measured maximum vibration velocity is14.26cm/s,and the particle vibration velocity shall not exceed 12-15cm/s,which meets the safety allowable vibration velocity of traffic tunnel blasting,so it meets the construction requirements.(4)Combined with the actual situation of 2 # tunnel ventilation shaft sinking in qinling are green,the excavating equipment selection and matching of drivage rate to speed up,to influence the efficiency of the rock drivage construction technique,blasting excavation and the lining of bolting and grouting is analyzed,the drilling blasting technology and scientific organization and management,etc.In order to achieve the purpose of raise shaft sinking efficiency,and auxiliary equipment,equipment,personnel and effective scientific management to improve the ventilation shaft of quick tunneling technology development. |
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