1、翻译部分Comprehensive evaluation of water-inrush risk from coal floorsWEI Jiuchuan1,*, LI Zhongjian1, SHI Longqing1, GUAN Yuanzhang2, YIN Huiyong11College of Geology Science and Engineering, Shandong University of Science and Technology, Qingdao 266510, China2Yanzhou Mining Co., Ltd., Jining 272100, Chi
2、naAbstract: Lower groups of coal seams are presently being mined in the Yanzhou coal mining area. We need to evaluate the riskfrom water-inrush from coal floors in order to have safe production in the lower groups of coal seams in mines. Based on a systemati ccollection of hydrogeological data and s
3、ome data from mined working faces in these lower groups, we evaluated the factorsaffecting water-inrush from coal floors of the area by a method of dimensionless analysis. We obtained the order of the factors affectingwater-inrush from coal floors and recalculated data on depths of destroyed floors
4、by multiple linear regression analysis and obtained new empirical formulas. We also analyzed the water-inrush coefficient of mined working faces of the lower groups of coalseams and improved the evaluation standard of the water-inrush coefficient method. Finally, we made a comprehensive evaluationof
5、 water-inrush risks from coal floors by using the water-inrush coefficient method and a fuzzy clustering method. The evaluationresults provide a solid foundation for preventing and controlling the damage caused by water of an Ordovician limestone aquifer inthe lower group of coal seams in the mines
6、of Yanzhou. It provides also important guidelines for lower groups of coal seams in other coal mines.Keywords: water-inrush from floors; fuzzy clustering; factors affecting water-inrush from coal floors; lower groups of coal seams;dimensionless analysis1 IntroductionThe evaluation of water-inrush fr
7、om coal floors is acomplex problem, related to many factors such as hydrogeology, engineering geology, mining conditions and rock mechanics1. So far, many theories and methods have been proposed to evaluate water-inrush from coal floors, such as the water-inrush coefficient method,the Down Three Zon
8、es Theory, a Four-Zone Theory, a Neural Network Method, a Multi-source Information Fusion Method and a Vulnerable Index Method2-7. At present, shallow lower groups of coal seams are being mined and deep exploration is in progress. We have to evaluate the water-inrush risk from coal floors in order t
9、o have security of production in the lower groups of coal seam mining.To rank the order of the factors affecting water-inrush from coal floors is a difficult problem. We introduce a dimensionless analytical method to solve this problem. Dimensionless analysis eliminates the impact of dimensions, mak
10、ing this evaluation index comparative, additive and subtractive. It converts raw data into new data by a particular calculation. In other words, it could eliminate the impact of the dimensions of the raw data8-10. We also introduce a fuzzy clustering method to address the problem of limitations in t
11、he evaluation of water-inrush from coal floors by the water-inrush coefficient method. Fuzzy clustering is a multivariate cluster method, which classifies many factors according to certain criteria11. It is a simple but efficient method in the evaluation of water-inrush risks from coal floors. The e
12、valuation results can provide a solid foundation for preventing and controlling the damage caused by water from the Ordovician limestone aquifer at the lower groups of coal seam mining in the Yanzhou coal mining area. It should also provide important guidelines for lower level groups of coal seam mi
13、ning in coal mining districts.2 General hydrogeological situation of mining areaThe Yanzhou coal mining area, a semi circle synclinal basin, is located in Yanzhou city and consists of seven coal mines, including the Nantun, Xinglongzhuang and Baodian mines. The Tangcun mine closed in 2002. The basin
14、 belongs to the Carboniferous-Permian (era). The strata include, from top to bottom, Quaternary, Jurassic, Carboniferous, Permian and Ordovician layers. The major coal seams are the 2nd and the 3rd seams in the higher group of coal seams, as well as the 6th, 16th and 17thseams in the lower
15、 group of coal seams.The east of Yanzhou coal mining area is cut by the Yishan fault and the south, east, north of the area are bordering coal seam outcrops. As well, its peripheries are bordering the Zouxi and Caowa water sources of the Ordovician limestone and Ziyang anticlines. Thus it is a relat
16、ively unattached hydrogeologic unit. There is an abundance of water in the shallow Ordovician limestone and Quaternary sandstone aquifers. The amount of water in other aquifers is not very large. In this mining area, most hydrological types are moderately complex, while they are simple in the Beisu mine and complicated in the Yangcun coal mine.3 Evaluation of factors affecting waterinrush from coal floorsUp till now, there have been many theories and methods conce
