孔—巷联合随采地震相关时差层析成像

煤矿井下回采工作面随采地震技术将采煤机作为震源，实现了动态精准、绿色智能探测的技术构想，可用于工作面内部静态地质异常体与开采动力地质灾害的超前探测。针对常规随采地震观测系统存在的成像盲区问题，提出孔–巷联合的随采地震观测系统设计方案，有效提高成像范围；基于地震干涉原理，采用频率域相关算法，对随采地震信号进行脉冲化处理，获得随采地震等效炮集；为解决随采地震CT层析成像中绝对走时难以获取的问题，提出直接利用相关时差进行CT层析成像的方法，求解过程中无需计算发震时刻，降低对初始速度的依赖。理论模型和实际资料测试结果表明:孔–巷联合观测系统有效扩大了成像范围；基于相关时差的随采地震层析成像方法可以对工作面内部进行速度成像，实现对静态地质异常体的探测；利用随采地震连续监测、动态成像的特点，还可实现对工作面内由于采动引起的应力集中区的实时动态监测，对工作面安全监测更有意义。 

Borehole-roadway seismic-while-mining tomography using correlation time difference

Using shearer as a source, seismic-while-mining(SWM) technology has realized dynamic, accurate and green intelligent detection in fully mechanized mining faces, and can be used to detect static geological anomaly and dynamic mining geological disasters within the work face. Conventional SWM observation system has the defect of blind area. To solve this problem, a new observation system with detectors installed in both roadway and within boreholes are proposed, which effectively improved the imaging range. Based on seismic interferometry principle, using frequency domain correlation algorithm, this paper turns the SWM signal to explosive source signal, and computes the equivalent shot sets. In SWM CT tomography, the absolute travel time is hard to obtain. therefore, a CT tomographic method that directly using correlation time difference was propose, so as to avoid calculating the exact time of seismic and reduce the dependence on the initial speed. The theoretical model and the actual data prove that using borehole-roadway approach, the imaging range has been effectively expanded. The SWM CT tomography based on correlation time difference can image velocity within work face, with static geological anomaly detected effectively. The continuous monitoring and dynamic imaging characteristic of SWM can also be used to dynamically monitor the stress concentration caused by mining in real time, which is more meaningful for working face mornitoring.