Study on the Influence of Coal Face Advancing Distance on Fault-Activated Water Inrush
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ORIGINAL PAPER
Study on the Influence of Coal Face Advancing Distance on Fault-Activated Water Inrush Yuben Liu . Hengze Yang . Chao Liu
Received: 21 July 2019 / Accepted: 12 February 2020 Ó Springer Nature Switzerland AG 2020
Abstract Water inrush in deep coal mines is closely related to geological structures such as faults. In order to study the influence rule of different coal face advancing distance (CFAD) on floor fault activation and floor rock mass failure characteristics, a mechanical model of fault activation was established with the 1315 working face of Anju coal mine as the research background, and the distribution of shear stress on fault plane and the influence rules of fault-activation under different CFAD are obtained. Then, FLAC3D numerical simulation software was used to further simulate and study the activation rules of floor faults and the characteristics of fracture development in floor rock mass. The results show the following: (1) When the coal face advances to a position of 80 m from the fault, the shear stress on the fault plane is sufficient to cause the fault-activation; When the coal face advances to a position of 20 m from the fault, the shear stress reaches a maximum and the fault-activation will reach a peak; (2) In the fault zone, fractures are derived from the bottom up under mining operation, but the development degree of fractures in the deep part is weaker than that in the shallow part. (3) Y. Liu (&) H. Yang College of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao 266590, China e-mail: [email protected] C. Liu Jinqiao Coal Mine, Jining 272200, China
Due to the existence of faults, a ‘‘oblate’’ damage and failure zone extending to the front and bottom of the coal wall gradually forms in the working face floor. The extension of this damage zone is first connected with the activated fault crack, and has formed advanced water inrush. Keywords Shearing stress Coal face advancing distance Fault-activation Floor water inrush Fluid– solid coupling numerical model List of symbols a The intersection of fault and coal seam h The intersection angle between fault and coal seam c Gravity density H The depth of coal seam k 1, k 2 The stress concentration coefficients of corresponding regions Q (KN) Concentrated force on the boundary of an infinite planar body q (KN/ Load collection degree(i.e. load per unit m) length) rx The normal stress along the x direction at any point of floor ry The normal stress along the y direction at any point of floor sxy Shear stress at any point of floor a Multiple of original rock stress sN Shear stress on the fault plane Y The vertical distance from coal seam floor
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Geotech Geol Eng
Abbreviations CFAD Coal face advancing distance 1 Introduction Mine water inrush is one of the major disasters in the coal mine production process. Many studies have focused on the prediction and prevention of inrush events in coal mining (Hofmann and Scheepers 2011; Lee et al. 2
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