The Study On The Propagation Of Blasting Vibration In Deep Excavation

The deep metal mines mining and the large-scale propulsion of Water Resources and hydropower and traffic engineering construction are undergoing major development in western china in recent years.Due to the intense tectonic activity,complex geological conditions and high in-situ stress of engineering,the damage and failure of surrounding rock caused by excavation blasting vibration are increasingly prominent.So studying the spread characteristics of the blasting vibration wave in deep rock mass,revealing the attenuation law of blasting vibration velocity and frequency are of great significance for the safe and efficient excavation(mining)of deep engineering.This paper is based on the drilling and blasting excavation of deep underground laboratory in Jinping.According to the blasting construction sequence of the laboratory and the characteristics of the engineering geological,the propagation law of blasting vibration in different blasting modes,geological conditions and different chamber structures were studied.The main contents and results are as follows:(1)First of all,the influence of sensor fixed way on the measuring accuracy was studied by experiments:the influence of surrounding rock loose circle on the measurement results was studied by installed the sensor in the rock surface and the different buried depth of pre drilled respectively,and the influence of the surface roughness of surrounding rock and steel support and other fixed way on the results of measurement were studied also.The results show that the good fixation,especially avoid the influence of surrounding rock loose circle can more really reflect the effect of rock vibration.(2)The sensitivity factor of the blasting vibration was analyzed by using the generalized absolute correlation degree model,and the blasting measurement results were fitted and analyzed by using least squares.The vibration wave propagation laws of the cut blasting,the caving blasting and the surrounding pore forming blasting were studied,and the influence of the typical macro structure,such as fracture zone,was studied also.The corresponding propagation formula is obtained,and the safe distance of blasting vibration and control the maximum charge of the same interval are given according to the maximum vibration velocity criterion.(3)Few influence factors are taken into account by traditional empirical formula,so the BP neural network model considering more factors was established to study the attenuation law of blasting vibration.Compared with the traditional empirical formula,the results shows that the BP neural network can well analyzed the blasting vibration characteristics.(4)Finally,the feasibility of monitoring rock burst by blasting vibration measurement system and rock burst strength were discussed.The results show that blasting vibration measurement system can effectively monitor the vibration signal generated by rock burst.The equivalent and scale of rock burst were studied through the experience formula method and BP neural network intelligent analysis method.