关键词: 采空区, 岩体损伤, 电阻率, 高密度电法, 上覆岩层

Abstract: Accurate characterization of overburden damage in coal mine goafs is very important for the evaluation of the stability of goaf sites. the damage of overburden can be characterized by using high-density electrical method to obtain the resistivity of overburden based on the characteristics of the resistivity change of the compressed rock . Based on the correlation between porosity, resistivity and volume strain, the expressions of rock resistivity and volume strain are derived, and use RFPA software to verify the resistivity characteristics of the compressed rock; a resistivity-based damage is established by analogy, and lead to the resistivity proportional coefficient to characterize the damage degree of overburden ; the method of resistivity detection, theoretical formula and the point-plane combination of borehole verification is used to determine the characteristics of the overburden three zones. The results show that the resistivity of compressed rock increases from the decrease of pore compression in the early stage to the increase of crack propagation in the later stage; the resistivity coefficient is greater than 1.6 at the overburden goaf and between 1.2 and 1. 6 in the vicinity of the goaf. In other areas, it is less than 1.2, which provides a theoretical reference for the determination of the overburden three zones.