Study On The Stability Of Ore-drawing Roadway Based On Blasting Dynamic Load

Due to the stope blasting has large charge,more times,limited underground space and other characteristics,the horizontal fan-shaped deep hole sublevel stopping method used on ore mining by Qianjiaping vanadium ore.And because of this,the damage of the adjacent roadway surrounding rock become increasingly apparent caused by the blasting vibration effect.Especially part of side wall has cracks,and small pieces of rock falling off the roof on the spot.Taking into account the importance of blasting vibration on the failure mechanism of surrounding rock could be maintain the stability of stope by the corresponding control measures,the influence of blasting vibration on the stability of surrounding rock is analyzed in this paper.The analyze is based on field measured vibration data as the basis,through theoretical analysis,regression analysis,FLAC3 D numerical calculation,and then put forward corresponding control detonation measures.The main results of this paper are as follows:Study on the attenuation law of blasting vibration and spectral characteristics.Firstly,investigation and research the engineering geological conditions,production process,the design of blasting parameters and the present situation of the destruction of the ore-drawing roadway on the middle section of +745,then design and implementation of+745 midsection stope blasting vibration test and record the vibration velocity,duration,the main vibration frequency and other parameters in deep hole blasting.Secondly,the attenuation law of blasting vibration wave in the area would be obtained after regression analysis of measured data,which provides a basis for the optimization of stope blasting parameters.Finally,analysis of a measured signal of stope by HHT and found the instantaneous energy points concentrated distribution in 50 Hz,and most of them are low frequency located in 10Hz~20Hz close to the natural frequencies of the adjacent buildings that very easy to produce resonance and causing the accident.Meanwhile,it also found the signal instantaneous energy distribution was mainly concentrated in the period of0.2s~0.4s that micro differential effect was not obvious.It is recommended to determine the largest single detonation loading and segments of detonators,in order to achieve the best vibration reduction effect.Numerical simulation study on the stability of ore-drawing roadway based on dynamic load.According to the engineering practice establish numerical calculation modeland measuring vertical vibration velocity as the dynamic load input waveform,then calculate the change of stress field,displacement field,plastic zone and velocity field in the surrounding rock of roadway separately under the condition of dead weight and dynamic load,in the +795 section of the mine roadway.The results showed that blasting vibration has little effect on displacement,stress and plastic zone of the surrounding rock(without supporting).But at the bottom of the roadway is more obvious than other regions,it indicates that blasting vibration has little effect on the roadway,and the main focus on the floor and corner.Compared with the roadway after bolting and shotcrete support,found that the shotcrete can further reduce blasting effect of vibration on the roadway caused by tunnel.After monitor the stress field,displacement field and velocity field with time of the particle around the tunnel(except the floor),found that the variation of stress and velocity with time and load input waveform is in general agreement.Meanwhile it found that the stress extreme value,velocity extremum and displacement(the same time)have the greatest change of tunnel corner,shows blasting vibration(explosion source is only located under the positive)is the greatest impact on the bottom of roadway.The stability monitoring of ore-drawing roadway.The monitoring results of roadway convergence deformation before and after blasting operation show that the convergence deformation in a normal situation,compared with the numerical simulation results.But in practice after multiple cumulative blasting,there will still be a certain degree of damage to the roadway at the top of the operating point and the damage of surrounding rock of roadway will be accumulated further of frequent blasting operations in the future,then over the safety threshold,resulting in the instability.Therefore,it is supposed to take the support measures to the dangerous area in time and adjust the blasting operation parameters to reduce the damage of the roadway.