Abstract
With the increase of mining depth in underground engineering, deep ground pressure has an extremely unfavorable impact on safety production and the economic benefits of coal mines and the control of the roadway stability in deep mines are gradually highlighted. In this study, the working face 14203 of the Zaoquan coal mine was taken as the engineering background, the deformation mechanism of surrounding rock in the deep-buried high-stress roadway was analyzed, and the hydraulic fracturing pressure relief technology in the advanced roadway was proposed for surrounding rock control. Finally, the numerical simulation and field tests were used to validate the comprehensive effect of the proposed technology. Without damaging the roadway stability in the working face, the hydraulic fracturing pressure relief technology can optimize the stress environment and stability of the roadway through the artificial control of the roof fracture position. The numerical simulation shows that under the action of hydraulic fracturing, the cutting slot is formed, the deformation and failure mode of the roof are changed, the stress of surrounding rock is reduced, and the development of the plastic zone of surrounding rock is limited. As a result, the stability of surrounding rock in the roadway is effectively protected. The field test shows that after the adoption of hydraulic fracturing pressure relief technology, the roof subsidence, floor separation, bolt stress, and cable stress decrease, and the deformation of surrounding rock is reduced significantly. Therefore, hydraulic fracturing pressure relief technology is verified as an effective method to control the large deformation of the surrounding rock in the deep-buried roadway.
Highlights
In recent years, the mining depth and mining scope have been continuously increased
The deformation characteristics of coal rock are changed from brittleness to plasticity, and the dilatancy and the impact risk of coal rock are increased
Erefore, the deformation and failure of surrounding rock should be effectively controlled under the strong mine pressure in deep mining to ensure safe mining
Summary
The mining depth and mining scope have been continuously increased. Compared with the shallow mining, the geological process characteristics and mine pressure behavior law under the condition of deep mining have been changed greatly: for the deep mine, the vertical stress (caused by the gravity) and the in situ stress are higher, and the tectonic stress field is more complex. Complex geological conditions and high ground stress fields often cause serious deformation and failure of surrounding rock [4, 5]. Yang et al [8] studied the stress process of bolt on the roof by three-dimensional numerical simulation, analyzed the time effect of bolt mechanical properties, and summarized the working mechanism of floor bolt He et al [9, 10] pointed out that in the deep coal mining, the rock mass medium is in the stage of large plastic deformation, leading to more significant nonlinear mechanical phenomena; as for the supporting technology, the coupling of the strength, stiffness, and structure between the support body and the surrounding rock should be considered. Theoretical analysis, numerical simulation, and field tests were employed to study the mechanism of the hydraulic fracturing pressure relief technology and its implementation effect. e research results can provide a reference for roadway stability control under similar conditions
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