1、 英译汉Height and detection of water flowing fractured zone in fully mechanized mining areaBaishan Xu1, Qi Li1, Zhihong Li2, Zhijian Haol, Guojun Gao3 1.School of Resource and Civil Engineering, Northeastern University, Shenyang, Liaoning 110004,China2.Institute of Geophysical Prospecting, Nanjing 1300
2、26, China3.Tiefa Coal lndustry(Group)Limited Liability Company Shenyang 110500, Chin AbstractAbstract: Coal mining like mining underneath buildings, roads, or waters changes the distribution of stress in rock mass, resulting in deformations between the roof and the surface, as well as crisscrossing
3、fractures in the mining rock mass. These fractures and deformations affect the mechanic behaviors of the rock mass, and to some extent control its stability. As mining continues, stress balance will be lost, which may lead to collapsing of the rock mass around stope. Therefore, the monitoring of wat
4、er flowing fracture zone of overlying strata is a vital problem. This paper studies the relationship between the water flowing fracture zone and mining by taking the fully mechanized mining underneath waters as an example. It concludes that the variations and distribution of fractures in the mining
5、rock mass can be revealed by P- and S-wave seismic survey, which ensures miming of coal seam safely. S-wave reflection survey can be used to detect the formations with water flowing fractures and characterize the development degree of the fractures. The validity of the proposed method was verified b
6、y drilling. The proposed method provides support for mining of coal seam of over 10m at onetime under water reservoir.Key words: SV wave Exploration, mined-out areas,coal seam, water flowing fracture zone, geophysical methodsIntroductionFor coal mining under buildings, roads, and waters, the carving
7、 zone formed from mining leads to the relocation of stress. The deformations and fractures from stope roof to the earth surface result in a complicated fracture network internal the rock mass. This impacts the mechanic behaviors of the rock mass, or even controls the stability of the cover rock to s
8、ome extent (Wu et al., 1994). Therefore, the knowledge about the distribution of fractures in the cover rock above coal mine is very important for studying the collapse of the mining rock mass, determining the mechanic parameters for stability prediction of building foundation over mine goaf, and as
9、sessing the strength and stability of restructured mining rock mass.Fractures grow upwards from the bottom as the work face advances. These fractures form different network corresponding to different work face. The foregoing network expands, closes or opens along with the work face advancing, which
10、complicates the fracture distribution of mining rock mass. On completion of mining and the rock displacement tends to stabilize, bed separation will basically close in the middle of the goaf. The height of the water flowing fractured zone under certain mining method and scale is the vital informatio
11、n as to determine whether coal mining under waters will give rise to seepage around the reservoir. Traditionally, this height is determined from the washing fluid used during borehole survey and numerical simulation. These methods are ones that infer the global from the local and may fail to reflect
12、 the real situation. For the coal seam and overburden bed with weak rock strata and heterogeneous hard rock strata, the overburden bed tends to deform seriously or non-uniformly. In such case, numerical simulation usually fail to yield desired results, and borehole survey also cannot keep track of t
13、he progressive destruction and instability, as well as the opening and closing of faults and joints. Seismic exploration with P- and S-waves is able to reflect the changes of fracture network in the mining rock mass. Thus it can beused to safeguard coal mining.1 Characteristics of the overburden bed
14、 deformation over the mining areaRocks around the mining goaf undergo complicated displacement and deformation after coal excavation. On its completion the overburden bed can be roughly divided into three zones: carving zone, fractured zone, and bending deformation zone (Yan, 1995). Carving zone is
15、the area where the overburden bed is completely collapsed. The rocks in the carving zone are characterized by irregularity, expansion on breaking, and poor compactness, which hampers roof regeneration and water barrier formation with the carving ground (China Coal Research Institute Beijing Mining R
16、esearch Institute, 1981). Above the carving zone is the fractured zone. Fractured zone is the area where rocks still keep their original layering structure though they are fractured, separated, and faulted. The distribution of the fractures in the fractured zone possesses a certain zonation. The carving zone and fractured zone are referred as water flowing fractured zone. This zone plays an important role
