1、翻译原文 Numerical investigation of groundwater outbursts near faults in underground coal minesLi Lianchonga, , , , Yang Tianhongb, Liang Zhengzhaoa, Zhu Wanchengb, Tang Chunanaa School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian 116024, P.R. Chinab Center for Rock Instab
2、ility and Seismicity Research, Northeastern University, Shenyang 110006, P.R. ChinaReceived 18 August 2010. Revised 13 December 2010. Accepted 13 December 2010. Available online 21 December 2010.AbstractPermeable geologic faults in the coal seam can cause intermittent production problems or unexpect
3、ed amounts of groundwater outburst from the underlying aquifers. With the acknowledgment of the basic mechanism for groundwater outbursts, the groundwater outburst along the fault zones in coal mines are numerically investigated using RFPA, a numerical code based on FEM. The fracture initiation, pro
4、pagation, and coalescence in the stressed strata and the seepage field evolution in the stress field are represented visually during the whole process of groundwater outburst. The numerically obtained damage evolution shows that the floor strata could be classified as three zones, i.e. mining induce
5、d fracture zone, intact zone and fault reactivation zone, in which the intact zone is the key part for resisting groundwater outburst and directly determines the effective thickness of water-resisting rock layer. With understanding of the evolution of stress field and seepage flow in floor strata, t
6、he groundwater outburst pathway is calibrated and the transformation of floor rock mass from water-resisting strata to outburst pathway is clearly illuminated. Moreover, it is shown that geometrical configuration, including inclination angle of faults and seam drop along faults, have an important in
7、fluence on groundwater outburst. Finally, based on geological, hydrogeology survey and numerical results, the mechanism analysis of groundwater outburst in an engineering case is studied, which can provide significantly meaningful guides for the investigation on mechanism and prevention of groundwat
8、er outburst induced by faults in practice.Research HighlightsThis study provides supplementary information on the stress distribution and failure-induced stress re-distribution that cannot be observed directly in situ or in experiments, within the areas of floor rock mass with the influence of fault
9、. This study gives an interpretation of the fracture initiation, propagation, and coalescence in the stressed strata and the seepage field evolution in the stress field during the whole process of groundwater outburst. The transformation of floor rock mass from water-resisting strata to outburst pat
10、hway is clearly illustrated with the fracture evolution. This study makes an assessment of safety regarding water-resisting floor rock mass containing a fault with different configuration, including inclination angle and seam drop. And concretely illustrate the influence of fault configuration on gr
11、oundwater outburst by a case study.Gadget timed out while loadingKeywordsGroundwater outburst; Geological fault; Rock failure Process; Numerical simulation; Underground coalmines1. IntroductionWhen the seam floor is not strong enough to resist the groundwater with high pressure, the groundwater can
12、break it and burst into the working areas in underground coal mines. This phenomenon is called groundwater outburst and can be a severe geological hazardous event if an unexpected amount of groundwater were to appear suddenly from the underlying aquifers through the fractured seam floor. This could
13、cause grievous casualties and heavy economic losses for underground coal mines.It is of vital importance to know when, where, and how groundwater outbursts could develop during mining processes ( Donnelly, 2006, Wang and Park, 2003, Wu et al., 2004, Yang et al., 2007, Zhang and Shen, 2004, Zhang et
14、al., 2009 and Zuo et al., 2009). Rock is a heterogeneous geological material which contains natural weakness at various scales. When rock is subjected to mechanical loading, these pre-existing weaknesses can close, open, extend or induce new fractures, which can in turn change the structure of the r
15、ock and alter its fluid flow properties ( Karacan et al., 2007, Oda et al., 2002, Schulze et al., 2001,Souley et al., 2001, Tang et al., 2002 and Wong et al., 1997). the mining conditions in coal deposits in tectonically stressed masses are characterized by a number of features that are manifestatio
16、ns of mine pressure. The distribution of stresses around a major fault zone that intersects the mine entry roadway is of considerable importance in determining the stability and safety of mining operations. When mining excavations are made, the re-distribution of the stress field leads to the initiation and growth of fractures, and potentially creates a highly permeable damage zone around these excavations. This dam
