Progress in investigation technology for coal mine goafs under buildings and structures in China

The investigation of goafs in the coal mine is a major technical problem that restricts the normal engineering construction and safe operation of the upper site. Looking back at the establishment of coal mine goaf prospecting technical specifications in China, the results obtained in the past three decades are reviewed in the goaf prospecting methods, the deformation prediction, stability evaluation, etc. Some representative problems are pointed out in the current actual investigation work, such as the poor guidance of the investigation outline, the inadequate integration of drilling technical requirements with the investigation work, the inability of engineering geophysical exploration to meet the investigation needs, the insufficient comprehensive analysis of the investigation results, and the lack of in-depth research on special rock and soil problems in the goaf site. In this paper, the future development trend of the standardization of prospecting work and the application of new technologies is prospected from the aspects of high-precision deformation monitoring, fine geophysical exploration, directional drilling and information technology. The direction of further research on geophysical inversion, in-situ test and evaluation, deformation monitoring and early warning of coal mine goafs are proposed, providing reference for the prevention and control of goaf disasters.