In situ Measurement of Hydraulic Properties of the Fractured Zone of Coal Mines

Excerpt

A review of the literature on the water inrush of underground openings under a condition of water flow reveals that insufficient attention has been devoted to the measurement of hydraulic properties of fractured zones, such as faults and zones of plastic damage generated by excavation or mining. A conceptual sketch of the fractured zone is presented in Fig. 1. The zone of floor damage is a zone of deformation and failure of the floor rock formation resulting from mining. In particular, groundwater inrush from aquifers underlying mining coal seams are usually induced when uncovering the fractured zone, which is a geological structure extensively distributed in the coalfields of eastern China (Bai et al. 2013). Moreover, the Ordovician limestone underlying the coal seams of coalfields in eastern China forms a confined karst aquifer containing an abundant supply of water and having very high water pressure (Zhang 2005). In this regard, the hydraulic properties in the fractured zone are important to deep underground engineering, particularly when an aquifer surrounds an excavation, for the reason that most water inrush accidents relate to the fractured zone (Fahimifar and Zareifard 2009; Qiao et al. 2013).

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