Tomographic imaging technology of front side of roadway based on excavation source of roadheader

The advanced seismic detection based on the seismic source of the roadheader use seismic wave generated by the cutting of coal wall and the falling of rock as the source of seismic and the advanced detection of the roadway is realized by continuously collecting seismic waves in the roadway for a long time and searching for reflected waves from it. In order to use continuous excavation seismic data to realize the imaging of the geological anomaly in front of the roadway, the principle of the excavation reflection wave imaging was analyzed, and the process of data processing and imaging was divided into five steps. Firstly, the excavation data was divided into many segments of a certain time length. Each segment was analyzed and selected according to the ratio of time in which roadheader was working well. The pulsed record was obtained through cross-correlation with the reference roadway, and then based on the direct groove wave in each pulsed record, the signal-to-noise ratio screens out qualified pulsed records. Finally, the ray-based diffraction migration method was used to image the front of the roadway and the side siding area. The excavation detection test was carried out in the return airway of No.1215 working face of Yushupo Mine of Yangmei Coal Group. The geophone arranged in the coal wall collected multi-day excavation seismic data, and the data was processed and imaged. The results show that pulsing the seismic data of the roadway machine source and using the diffraction migration method can realize the imaging of the front fault on the side of the roadway head. Moreover, the tunneling seismic data contains a large amount of invalid data and it is an important step to evaluate data quality and screen the data to improve imaging quality. There is no theoretical basis for directly imaging the front of the tunneling work. Inferring the intersection of the front fault and the extension line of the roadway from the imaging results can realize the prediction of the fault location in front of the roadway.