| Drilling and blasting method is the main rock-breaking method in mining.With the continuous expansion of mining scale,the volume and charge of blasting are gradually increasing,and the blasting vibration is also greater.Frequent blasting vibration has an impact on the safety and stability of surrounding rock of roadway and its support,underground chamber,pillar and roof.Many experts and scholars at home and abroad have studied the dynamic load of blasting in open-pit mine,underground mine blasting,tunnel excavation blasting and so on.However,there are few studies on the dynamic response of blasting dynamic load to surrounding rock and support of roadway,underground chamber,pillar and roof.On the basis of consulting a large number of domestic and foreign research data on blasting,this paper takes Houping mining area of Xingfa Group as the research object.Firstly,the types and characteristics of underground structures in mines,the generation and propagation mechanism of blasting seismic waves,attenuation and absorption,cumulative damage characteristics of blasting vibration,stability of underground structures in mines,common failure forms and seismic reduction measures are studied and analyzed by theoretical analysis method.Secondly,field investigation and measurement are carried out in combination with detailed investigation report of Houping mining area,and the workers in Houping mining area are analyzed.Then ANSYS/LS-DYNA is used to simulate roadway excavation blasting,and the dynamic analysis of deep-hole excavation blasting is carried out.Finally,the finite difference software FLAC3D is used to establish a numerical model to study the dynamic response of surrounding rock,bolt support structure,underground chamber and stope pillar and roof.The following conclusions are drawn:(1)Through the test of P-wave velocity measurement of rock in drifting roadway in Houping mining area,and the analysis of the measurement results,it can be seen that the average P-wave velocity of rock is not more than 2.532 Km/s,the maximum wave impedance of rock is 7.241 kg/m~3.m/s,and the average rock hardness factor f=10.The rock explosibility of drifting roadway in Houping mining area can be judged to be of medium grade.(2)Using finite element software ANSYS/LS-DYNA to simulate the blasting process of roadway excavation,the numerical simulation results show that the explosive stress wave generated by explosive explosion in rock mass contains the compression phase at the initial time and the tension phase at the later stage,and the action time of compression phase is shorter than that of tension phase;the explosive stress wave generated at different explosion sources has propagated.There are obvious stress interaction areas in the process,especially in the cutting part and the first circle of auxiliary holes,which can accelerate the failure rate of rock and soil,and also show the continuity of explosive stress wave in the propagation process.(3)The finite difference software FLAC3D is used to establish the blasting and mining model of roadway excavation.The dynamic response of surrounding rock and its supporting structure,underground chamber,pillar and roof to blasting dynamic load is studied.The numerical simulation results are analyzed and the corresponding conclusions are drawn. |
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