Control Blasting In A Road Tunnel In The Pilot Study

At present, the technology of controlled blasting has been tested and applied in the tunnel construction at home and abroad, and achieved some success. With the rapid development of transportation networks, existing routes can not meet the needs of transportation, more and more new highway projects will be constructed, including many tunnels,Because of the limitation of various factors, such as topography, geologic conditions and transportation etc. the geological conditions of most tunnels are not well and surrounding environments are very complex.Then, In the course of construction, the safety of the surrounding facilities will be inevitably affected, therefore, the control of blasting vibration produced in the construction of new tunnels is very important and significant.This paper mainly studies the crack mechanism of smooth blasting technology, underholing technique commonly used in tunneling, monitoring and analysis of blasting vibration, theoretical calculation of blasting parameters and control of field test blasting project.First, a theoretical research and analysis of crack mechanism of smooth blasting and factors on affected smooth blasting is introduction,Then, based on the theoretical analysis and comparison of tunnel cutting technology used in tunnels, a trough technology most suited to dig this tunnel project is selected.According to rock mechanical parameters, the selected range of control blasting parameters in this project is calculated,Finally, field tested is conducted on the selected basic parameters of the controlling blasting, in the experiment, monitoring the blasting vibration generated by blasting, and using regression analysis to deal with the data collected on site, combining with geological conditions local environment and blast effects, according to previous experiences, determine the parameters of control blasting which is suitable to this tunnel construction, provides a reasonable proper construction technology of controlled blasting to get the most good control of blasting effect.Based on the excavation of the friendship highway tunnel of An Jin Expressway, Field test on the application of control blasting in tunnel construction under the complex environment.First of all, based on the theoretical research and analysis of the technology of Smooth Blasting and the underhole technique commonly used in tunnel construction, combined with geological conditions and local complex environment, a control blasting test scheme with three kinds of various blasting parameter was determined.Field test was carried out on the various design plans, and monitoring the blasting vibration generated by test, through the application of multiple linear regression function of Delphi, based on the regression analysis of data collected on site, the value of K and a was obtained.Caculating the vibration velocity generated by blasting according to Sa Tao Minkowski formula, according to the relevant provisions of the national standard《Blasting Safety Regulations》GB6722-2003, making proper evaluation on the blasting vibration test on-site.Finally, compared the effects of several controlled blasting programs, combined with the actual geological conditions and local environmental of the friendship highway tunnel, reference to previous experiences and lessons in tunnel construction, selects a reasonable and effective controlled blasting program most suitable for the friendship highway tunnel construction.The success of controlled blasting in the friendship highway tunnel tests has laid a foundation for the promotion and application of controlled blasting in future tunnel construction on complex circumstances. In addition, the test data and parameters obtained as well as the monitoring methods are helpful to similar tunnel construction in future.