Characteristic of the water-conducting fracture zone development in thick overburden working face with extra-large mining height in western mining area

In order to obtain the fracture development characteristics of the working face with extra-large mining height under the condition of thick overburden and medium mining depth in mining areas in China's western regions, this paper adopted a comparative study by combining empirical equations, numerical simulation and field measurement in the panel 12401 of the Shangwan coal mine.The results show that the empirical equations drawn from data from the typical geological conditions of mining areas in eastern and western China are difficult to apply to this panel with extra-large mining height, thick overburden and medium buried depth.The prediction values of the empirical equations based on data from the geological condition in the western mining regions are generally higher, which are significantly smaller in the eastern mining regions.The value predicted by the numerical simulation based on the damage constitutive model is closer to the measured value than those derived from using empirical equations, with a relative error of less than 5 %.The paper obtained the characteristics of the water-conducting fracture zone development: due to the existence of soft and hard rock in the overburden, the water-conducting fracture zone develops upward as a step, and the shape changes from "arch"(three-dimensional "shell") to "saddle"(three-dimensional "basin shape") with the variation of mining degree.