Study On Three-component Transmitted Wave Characteristics And Channel Wave Imaging In Working Face

Seismic exploration in underground coal mines has obvious technological advantages,which are as follows: close to the target body,long penetration distance;not disturbed by unfavorable factors on the ground;and channel wave seismic exploration also has the advantages of strong energy,high signal-to-noise ratio,and many available information.At present,the detection of geological anomalies in mining face by channel wave is a research hotspot.Therefore,it is of great theoretical significance and practical value to study the transmission detection and imaging of channel wave around typical coal seam erosion zone and fault structure.In this paper,theoretical analysis,numerical simulation and field test are used as research methods.Erosion zone models with different sizes and scouring degrees,fault models with small angle of strike and contact roadway are established.Threedimensional simulation is carried out based on high-order staggered grid finite difference algorithm.The snapshot characteristics,velocity records,dispersion characteristics and spectrum characteristics of wave field are compared and analyzed.Channel wave eigenvalue imaging and energy attenuation imaging are performed for different component data.The results are as follows:(1)For the erosion zone model,the more intense the coal seam is scoured,the larger the horizontal range of the erosion zone is,the more obvious the attenuation of groove wave is in the erosion zone;the channel wave of X component and Y component has significant attenuation in the erosion zone;the channel wave energy of Z component is the strongest and the attenuation is weaker;after a period of time,the channel wave energy will become stronger again,the Y component will not become stronger,the channel wave amplitude of Y component is more sensitive to the erosion zone.(2)When the horizontal range of the erosion zone is fixed,the vertical scouring degree of coal seam will only affect the development of channel wave,but has no effect on P-wave and S-wave;Compared with disconnected coal seam,the channel wave disconnected in the erosion zone,has smaller amplitude and lower frequency;The frequency dispersion of Z component channel wave is more significant than that of X and Y component;the energy attenuation inversion of X,Y and Z component based on eigenvalue constraints is abnormal in the scouring zone.Y component imaging is the best.(3)The snapshots of wave field and seismic records of faults with small angle are complex under the condition of contact roadway.Contact roadway will block the propagation of direct channel wave.The imaging inversion effect of the three components of the channel wave is good,and the imaging effect of the Y component is the best.The energy attenuation inversion of the three components of conventional channel waves is not good,and it is necessary to carry out the energy attenuation imaging constrained by the channel wave characteristics.The results after constraints show that the imaging accuracy is significantly improved.(4)SCT 2.0 mine multi-wave and multi-component seismic data processing module is developed based on Visual C++.net platform.Field exploration tests were carried out on typical stope in jining mining area of Shandong province and yangquan mining area of Shanxi province,detecting erosion zone,fault,contact roadway and collapse column,and channel wave eigenvalue constrained energy attenuation imaging is carried out.The empirical results show that this method provides technical guarantee for safe and efficient mining in the working face.