外文翻译-利用有限元法研究livezeni矿3号煤长壁开采对地表变形.doc

1、翻译部分：GROUND SURFACE DEFORMATION USING THE FINITE ELEMENT METHOD, IN CONDITIONS OF THE LONGWALL MINING OF THE COAL LAYER NO. 3 - LIVEZENI MINEIlie ONICA*, Eugen COZMA*, Dacian Paul MARIAN*The Livezeni Mine is situated in eastern part of the Jiu Valley coal basin (Romania) and produces about 0.5 milli

2、on tons of hard coal (presently, in totality from coal layers no.3). In the case of this thick and gentle coal layer, the mining methods are by use of the longwall mining technologies with roof control by rocks caving. In this paper, it is presented the analysis of the complex deformations of ground

3、 surface, as a consequence of superposed effect of three mining panels. Also ,it is analysed the ground surface subsidence phenomenon using the 2D finite element method. The modelling is made in the elasticity and the elasto-plasticity behavior hypothesis. The obtained results are compared with the

4、in situ measurements data basis.Keywords: subsidence, horizontal displacement, stress, finite elements.GeneralitiesThe Petrosani Hard Coal Basin, under the management of the Hard Coal Company of Petrosani, contains the most important hard coal deposit of Romania, with a balance reserve about on bill

5、ion tons of coal. This coal deposit was known and mined since the year 1788, as far back as the Austro-Hungarian Empire 1. But, the intensive coal mining of this deposit began in the same time with the Romanias industrial isation,after the Second World War, reaching after 1980 the over 9-10 millions

6、 tons of coal per year. Due to Romanian industry reorganisation, after the year 1990, in conformity with the new demands of the market economy, the coal production of this basin was reduced to about 3.5 millions of tons per year, from which 0.5 million are obtained from the Livezeni mining field. Fr

7、om the beginning this coal deposit was split into 16 mining fields, from which following several successive reorganization and closing stages, only 7 mining fields are left in activity.The complicated deposit tectonics determines the delimitation in geological blocks of reduced extent (most of them

8、varying between 200 and 300m) and an equally technical difficulty in mining. Moreover, there occurs a methane gas emission (of over 10 to 15 methane m3/coal ton) and there is a marked tendency of coal self-ignition.In this mining perimeter, through the geological research works, there was identified

9、 a number of 18 coal layers, of which the most economical importance having the coal layer no.3 (48%) and coal layer no.5 (12%). The sedimentary rocks complex, in which these coal layers are present, consists in rocks deposits which belong to Superior Cretaceous, Neocene and the Quaternary.The subje

10、ct of this study consists in the underground mining influence analysis on the ground surface of three adjacent mining panels (panel (3-4), panel 5 and panel 6), situated on the coal layer no.3, block VI A. Coal layer no.3, for these panels, was mined in inclined slices (about 2.5m thickness) with th

11、e longwall mining system, complexly-mechanized (powered support SMAP2H, shearer 2K52-MY and armoured conveyerTR-7) and roof control by caving.The underground excavations sizes results from the coal mining corresponding of these panels are presented into Table 1.Table 1 The average sizes of the minin

12、g panel of the coal layer no.3, block VI AFigure 1 The monitoring station of ground displacement and deformation of Livezeni MineGeo-mechanical characterizationAs the deposit genesis is sedimentary, the most frequent rocks in the basin are: limestones, marls, argillaceous or marly sandstones,congome

13、rates,etc., their strength ranging between 1516 MPa up 5060 MPa, sometimes even more. Mainly, they are rocks of relatively low stability The main factors that contribute at the definition of the stress and strain state surrounding the excavations generated by the coal layers mining with the roof roc

14、ks caving, in the Jiu Valley coal basin, are the following: the excavation sizes, the layer dip, the coal and surrounding geo-mechanics characteristics, the mining depth, the face supports characteristics, the face advancement speed, the distance from the adjacent panels, the distance from nearby co

15、al layers, etc.The average values of the main mechanical and elastic characteristics of the rocks used in the ground surface deformation analysis, in the Livezeni Mine conditions, are shown in the Table 2.Table 2 The average values of the geo-mechanical characteristics of the roof and floor rocks of

16、 the coal layer no.3 .As a result of the measurement analysis made on the ground surface under the underground mining influence, so as to find the optimum design parameters of the main safety pillars, the limit angles of subsidence have been set for the different coal mining fields of the Jiu Valley coal basin 9.The values of the li