Three Dimensions In-seam Wave Field Simulation And Detection Method Research Of Working Face Faults

With the continuous improvement of coal mining mechanization,the fault within the underground working face has become a critical factor affecting mining safety and efficiency.Due to the limitations of ground geophysical prospecting and down-hole radio wave perspective method for detecting faults,there is a need to develop a down-hole geophysical prospecting method with short range,large penetration distance,and high precision,to identify the fault,which affects safe mining.Channel wave's receiving point and seismic source are close to detection targets,it has the characteristics of large penetration distance,high frequency,strong energy,and high signal to noise ratio,and possesses obvious advantages in the detection of small faults in underground wells.In this paper,we conducted three-dimensional channel wave elastic wave field simulation using GPU parallel algorithm,analyzed the characteristics of the channel wave field for the fault at underground working face,and discussed the resolving ability of the transmission channel wave for detecting faults.The fault drop was predicted and the observation system was optimized to improve the capacity and precision of channel wave to detect faults.Using CUDA programming techniques and optimization technology,this paper studied the high-order finite-difference numerical simulation of three-dimensional channel wave's fast and high-precision staggered-grid based on GPU parallel computation.It reduced the storage problem in three-dimensional numerical simulation,and had high accuracy in simulating three-dimensional channel wave field of the fault.Compared to the computing results based on CPU platform,this simulation occupied less memory with higher computation speed.Through the analysis of channel wave dispersion,the frequency near Airy phase was selected as the wavelet frequency,and a series of fault models of critical geological parameters for faults at underground working face were established to simulate fault drop,inclination,direction,top and bottom lithology,and combination pattern.The dispersion analysis was carried out and the tomography CT imaging was improved.The resolving ability of transmission channel wave to detect faults was discussed theoretically.The numerical simulation analysis showed that the average attenuation coefficient of the channel wave amplitude increased with the increase of the fault drop,and decreased with the increase of the coal seam thickness.The relational expression between the attenuation coefficient of channel wave and the fault drop at certain coal thickness was derived,and the relationship plate diagram of average attenuation coefficient,fault drop,and coal thickness was made.In order to improve the lateral resolution of the channel wave toward the fault,we tried the channel wave attribute RGB fusion method,and improved its signal to noise ratio and resolving ability.We applied the average amplitude attenuation coefficient,the fault drop and the coal thickness relation plate diagram,and the channel wave attribute RGB fusion method to interpret the actual data.The interpretation of the fault drop was in good agreement with the actual disclosure of the tunnel and was credible.Through forward modeling,based on CT imaging results and the two criteria of measured relative error and coverage times,we discussed the capability of channel wave observation system to detect faults at working face,and optimized the observation system for its application to engineering practice.A set of high-precision fault detection method based on transmission channel wave was established.