1、英文原文Relationships between gas reservoir and the evolution of stope Surrounding rock fracture at the process of mining the Closed distance protection layerAbstract: Overburden rock movements and fracture developments occur during mining activities. Consequently, relief gas reservoirs and migration in
2、 coal seams being mined as well as in near distant coal seams appear. We considered a gas disaster management project and rules on stope relief of gas flows together and explored a gas reservoir and the evolution of stope surrounding rock fractures in the process of mining near distant protective la
3、yers by physical simulation, numerical simulation and field testing. Different techniques provide evidence of the rules of interaction of gas reservoirs and the evolution of surrounding rock fractures and are able to find accurately the gas-rich regions around the stope. Finally, we found that these
4、 rules can provide a basis for taking measures to prevent gas accidents in the protective layer of the coalface as well as for demonstrating and designing programs to drain high concentrations of gas from the gob.Keywords: physical simulation; numerical simulation; gas reservoir; evolution of fractu
5、res1 Introduction Given the complexity of the migration of adjacent coal seam gas and gas reservoir characteristics during mining operations of closed, distant protection layers, studies of gas drainage theory and treatment technology for gas disasters do not consider systemic and organic combinatio
6、ns of mining coal seams and pressure relief gas reservoir of these distant coal seams. Neither are the rules of migration of gas and the movement of mining overburden rock and the evolution of rock fractures considered, although previous studies have taken into account the effect of antireflection a
7、nd pressure relief of mining coal seam roofs and floor rocks. But these investigations did not provide more accurate determinations of gas-rich regions around stopes and therefore, could not offer a scientific and complete unified theory of control of gas disasters and stope relief gas flows in gas-
8、rich regions. In this study, we make use of physical simulation, numerical simulation and field measurement in order to find pressure relief gas reservoirs in mining coal seams and closed distant coal seams and as well as rules of migration of gas and the movement of mining overburden rock and fract
9、ure evolution. 2 Theoretical basis Roofs and floors of coal seams are composed of a number of different natural layers of coal. When coal is produced, the roof is left to a certain extent, but some rocks from the roof may fall. With the face advancing more hard roof rocks roof from the key inter-lay
10、er may be falling, which is referred to as first weighing. After that, as the face continues to advance the key inter-layer will drop over a particular cycle time and periodic weighing is formed at the coalface. According to research results from mine subsidence studies and roof rock control studies
11、, events such as caving, separation breaking and bending the sinking three-zone in the overlying strata of the gob occur. The caving zone experiences caving, compression and compaction processes. In the separation breaking zone, also known as the fracture zone, fractures will appear, which may becom
12、e fully developed in the compaction process. When the mining area reaches a certain level of production, fractures located in the middle of the gob roof rocks tend to become compacted, and developing connected separation fracture zones start to form around the gob area, with shapes similar to the O-
13、X-formation when the main roof rock breaks, Academician Qian ming-gao called it the O-ring. When an O-ring appears, more attention is paid to the pressure relief gas drainage in gobs, but how to find relief gas-rich regions is the key to drain gas efficiently.Fig. 1 Mechanics of the formation of the
14、 annular fracture ring3 Physical simulation and analysis The mining environment of the Wu8-19190 face of the No.4 mine in Pingmei is used as our simulation model The display of the model of the former mine is shown in Fig. 2.Fig. 2 Display of model before mining In the process of simulating producti
15、on at the working face in the laboratory, the roof overlying the rock fracture zone experiences a decline in relieve, buckling, cracking, extensional faulting and crack shrinking during mining, showing the evolution of the closure process, which has a direct impact on gas desorption, flows and the r
16、eservoir. During production at the coalface, the rock above the coal seam is constantly falling. When the face has advanced to about 180 m, the height of the coal caving zone above the coal seam is about 09 m, the drawing place for the falling rock is about 20 m and the height of the fracture zone is between 1028 m.Fig. 3 Map showing the distribution of a fracture zone after the collapse of the working face In the course of coal mining, t
