Study On Blasting Vibration Characteristics Of Surrounding Rock And Dynamic And Static Response Of Goaf

Due to the characteristics of the occurrence of ore bodies and the selection of mining methods,a certain gold mine in Fujian Province has resulted in the formation of goafs in the mining area,and at the same time,some areas in the goafs have also assumed the function of the mine roadway.The blasting production operations adjacent to the stope caused some damage to the pillars and roofs in the goafs.The goafs and the stope were adjacent to each other.Small-scale cracks and small-scale roof fall occurred in some areas.In this paper,mining geological parameters are obtained through mine geological survey,rock tensile strength is measured by RMT-150 c rock press,GY-90 borehole elasticity modulus is measured by mineral elastic modulus,and DASP2006 data acquisition system is used to determine the primary wave velocity of rock mass.In the regional rock mass mechanics parameters,the Blast mate-III blasting vibrometer was used to monitor the blasting vibration signal in the goaf,and the vibration signal was processed and analyzed using MATLAB software.Combining the test and monitoring results,the stability of the goaf was analyzed comprehensively through theoretical analysis,linear regression and FLAC3 D numerical simulation,and the safety and safety criteria of the goaf were proposed.Obtain the following research results:(1)After sampling the mine rock mass,conduct indoor uniaxial compression and Brazilian splitting test to obtain rock uniaxial tensile strength 68.08 MPa and uniaxial tensile strength 7.35 MPa.The rock mechanics parameters are based on the Hoek-Brown criterion.Reduction;In-situ Modulus Modulus Testing of On-Site Rock Mass,P-wave velocity test;initially complete determination of regional rock mechanical parameters.(2)By monitoring the blasting vibration data in the +575m goaf,the parameters such as the vibration velocity and duration of the particle are obtained.The linear regression of the measured data by the Sa Dawowski formula shows that there are certain differences in the attenuation law of the anisotropy in the goaf.The attenuation coefficient has a maximum value of 1.68 and a minimum value of 1.58.The HHT method was used to decompose and analyze the monitoring signal.It was found that the main vibration frequency of the vibration signal in the free space was in the low-frequency region of about 50 Hz,which was close to the frequency of the rock body in the free space,which easily caused resonance.The signal energy extremes were also distributed in the In this frequency band,according to observation of the blasting vibration waveform,there are multiple peaks in the energy,indicating that the effect of the differential start is not obvious and should be improved.The instantaneous energy of the signal generally reaches its maximum at 0.5s,and the instantaneous energy is applied to the time using MATLAB software.The integral gives the total input energy TIE as a safety criterion for blasting.(3)The numerical calculation of the stability of goaf under the action of blasting dynamic load uses the +575m goaf as a prototype to establish a three-dimensional model of the goaf.The measured blasting waveform is used as the dynamic load input to the adjacent working area of the gob area to simulate static excavation.With the input of blasting load,the stress field,displacement field,plastic zone distribution and ground subsidence under two conditions are calculated.The results show that the input of blasting load has certain influence on the stress,displacement and plastic zone distribution of the goaf;the tensile stress is mainly concentrated on the edge of the roof,and the compressive stress has a significant influence on the position of the middle of the pillar and the inflection point;the input of the load is accelerated.The dilatancy expansion of the mine house increases the horizontal displacement.The maximum value of vertical displacement is near the source side,and the surface settlement increases.The tensile plastic zone of the roof increases,and the surface plastic zone of the pillar increases significantly.Blasting the load numerically has some impact on the mined-out area,and the hazardous areas shown in the analysis results should be monitored and supported.