| As the most commonly used rock breaking method during the current ore body excavation,the blasting excavation is extensively employed for its economy and efficiency.However,blasting is an excavation method with its own destructive nature,which will not only break the ore body,but also cause damage to the surrounding rock.Therefore,it is of great significance to investigate the impact of blasting excavation on the stability of adjacent roadway and the law of rock damage.This paper aims to monitor and analyze the on-site blasting activities,explore the attenuation and energy distribution law of blasting vibration wave,and adopt the numerical calculation software FLAC3Dto simulate and examine the influence law of blasting activities on the stability of adjacent existing roadway among multiple angles,so as to provide theoretical guidance for engineering on-site construction.The main research results of this paper are presented as follows:（1）Through the analysis and processing of the monitoring data of the blasting site,the attenuation law of the vibration wave of the surrounding rock in the blasting monitoring area is obtained,and on the premise of the maximum allowable particle velocity,the relationship between the minimum blasting center distance and the maximum explosive quantity has been deduced.Meanwhile,it is comparatively observed that among the vibration waves in the three directions,the tangential and the vertical direction hold the largest and the smallest rank,respectively.In addition,the frequency of the blasting signal is mainly concentrated in 300Hz,especially centered on100Hz,which indicates that the blasting energy involved in this area is proved to be the largest.（2）The dynamic calculation of the model is carried out to explore the influence law of blasting activities on the stability of adjacent roadways.It is recognized that compared with the static load,when the blasting load is applied,the horizontal and vertical displacement of adjacent existing roadways will increase to a large extent,and the plastic zone and stress distribution situation will become more complex.Moreover,the surrounding rock in the middle and upper part of the vertical wall on the blasting side is mostly affected by blasting.Furthermore,the vibration velocity distribution of the existing roadway can be listed according to the sequence from large to small:the vertical wall on the blasting side to the top of the roadway,the area above the vault on the blasting side of the roadway,the bottom of the roadway on the blasting side and the area on the back blasting side.In the mean time,the vibration curve acquired by numerical simulation is well fitted with the field blasting monitoring curve,which proves the high reliability of the numerical calculation results.（3）The blasting simulation calculation is performed for the models under different initial conditions.It is relatively noticed that the parameters,such as the displacement and stress of roadway surrounding rock,gradually increase with the rise of roadway buried depth,and the greater the buried depth,the more huge the impact of blasting activity on the surrounding adjacent roadway will be generated.Simultaneously,the support parameters,such as the optimization of roadway bolt length and plain shotcrete thickness,etc,will strengthen the integrity of roadway surrounding rock,after that it can resist the impact load caused by blasting.It is proved that the appropriate support of roadway around blasting activity is an effective measure to prevent instability and failure accidents.（4）The use of three-dimensional reconstruction and envelope drawing technique can effectively reflect the numerical calculation results and provide a completely new idea for numerical analysis.In particular,the three-dimensional reconstruction technology can directly observe the three-dimensional changes inside the model,which makes it more advantageous to adopt the numerical calculation software to simulate and investigate the rock damage mechanism. |
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