The characteristics of mining induced stress fluctuations in broken rock mass over one kilometer deep coal mine

Abstract

Mine pressure is critical to the safety of working face. Evaluating the working resistance accurately of the stope hydraulic supports is one of the most effective and direct ways to reflect the overall stress characteristics of the roof and the deformation, movement and destruction of overlying strata. Due to the complex breaking form of the roof, the working resistance of the hydraulic supports at different positions of the mining face varies in different ways. One can obtain the pressure of hydraulic support system by pressure monitoring and analyze its fractal characteristics. Through spectrum analysis, a new parameter called accumulation power spectral density is defined which is used to describe the difference of working resistance of stope hydraulic supports. The results show that the fractal dimensions of face-end supports are smaller and face-end supports are unco-ordinated. Through in-situ monitoring, it is found that the mining stress has unstable periodic fluctuation characteristics. The conclusion can provide reference for rational selection and optimization of the similar-mining lay-outs.

Investigation of Dynamic Behaviour of Four-Leg Hydraulic Support under Double-Impact Load

“…By establishing the catastrophe mathematical model of the basic roof, the influence of the fracture position on the roof impact load amplitude has been studied [10] and [11]. Though establishing the stope numerical model using UDEC, Liu et al analysed the harmfulness of rock burst under different impact velocities [12]. Tan et al analysed the rock properties, coal rock height ratio, and other parameters on the occurrence frequency and strength of rock burst and proposed a new impact energy release index (considering time effect) and coal seam impact performance evaluation method.…”