Abstract
Hidden disaster-causing factors in coal mines are key geological factors that restrict the safety, high efficiency, green and intelligent mining, and transparent geology is an important technical means to realize the detection of hidden disaster-causing factors in coal mines, among them, geological structure transparent exploration is the most important. In order to build a transparent exploration system for hidden disaster-causing factors of geological structure that applies to different geological conditions or coalfield areas, first, based on analysis of factors causing hidden structural disasters, technical system of rapid investigation of factors causing structural hidden disasters is put forward, which is based on the regional structural analysis and the joint investigation of the ground and underground, effectively delineate the mine geological structure anomaly development area and analyze its distribution law. Based on the previous borehole data and 3D seismic data, the coal seam thickness, fault structure and roof and floor structure undulation patterns are analyzed. Comprehensive technical means such as channel wave exploration, directional drilling, advanced geophysical prospecting, earthquake while mining/driving, cuttings recording, rapid realistic description of roadway are adopted, further realizing the gradual transparency of the geological structure of the mining face, adopting the methods of theoretical analysis, engineering analogy, numerical simulation, similar material simulation, field engineering verification. Correlation between geological structure types, attribute characteristics and mine disasters, such as coal seam thickness, coal rock mass structure, gas emission, gas pressure, roof strata behavior, is analyzed. Response law of gas parameters and roof/ground pressure disasters in different areas of the mining face passing through the fault structure under the mining condition is studied. Monitoring and early-warning of the hidden disaster-causing factors of the face structures are realized by selecting the threshold value of the characteristic parameters, and the digital expression of the different geological structures and their disaster attributes is realized by using the digital technology, 3D transparent display of hidden disaster-causing factors is realized by modeling software. The technical system of geological structure exploration with 4 levels of regional structure geology research, exploration of hidden disaster-causing factors, scientific evaluation of disaster-causing threat and geological structure transparency is constructed, and carried out engineering practice in Tunbao Coal Mine. the results show that the types of geological structures in coal mine are complex, and there are not only graben type, barrier type, echelon type and flexure type of fault structures, but also small-scale scouring zone, fault and fracture zone. Complex geological structure is the key geological factor to induce mine gas outburst, roof disaster, stress concentration and mine rock burst. The influence of faults on stress concentration of roadway is 10 ～ 15 m, and the influence on working face is 20 ~ 30 m. There are gas enrichment areas in the working face, the distribution of gas content and gas emission has obvious zonation, and the zonation is controlled by faults. The content of coal seam gas and the amount of gas emission show logarithmic correlation with the distance between the working face and the fault, and increase obviously at the distance of 25 m from the fault, and change little in the area of more than 25 m, in the region less than 25 m, it increases exponentially with the decrease of distance. 20 m before and after the first pressure position and 30 m after the face-to-face are medium impact danger areas, the coal pillar affected area in goaf, 50 m before and after the final line, and 30 m before and after the fault with drop greater than 4 m are weak impact risk areas. The overlapping area of hidden disaster-causing factors such as rock burst, roof and gas, is the key area of disaster prevention and control. The research result realizes seamless connection between the hidden disaster-causing factors of geological structure and the mine disaster, and provides a feasible technical path for the development of traditional geological exploration in coal mine area to digitalization and intelligentization.
DownLoad: