外文翻譯---數(shù)值模擬中巖體力學(xué)特性的工程與實(shí)驗(yàn)關(guān)系

1、中文 中文3090字出處： 出處：International Journal of Rock Mechanics and Mining Sciences, 1997, 34(2): 289-297The Relation Between In situ and Laboratory Rock Properties Used in Numerical ModellingMohammad N, Reddish D J, Stace L RI

2、NTRODUCTIONNumerical models are being used increasingly for rock mechanics design as cheaper and more efficient software and hardware become available. However, a crucial step in modelling is the determination of rock ma

3、ss mechanical properties, more precisely rock stiffness and strength properties.This paper presents the results of a review of numerical modelling stiffness and strength propertiesused to simulate rock masses. Papers whe

4、re laboratory and modelling properties are given have been selected from the mass of more general modelling literature. More specifically papers that have reduced stiffness and/or strength parameters from laboratory to f

5、ield values have been targeted. The result of the search has been surprising: of the thousands of papers on numerical modelling, a few hundred mention laboratory and rock mass properties, and of those, only some 40 appea

6、r to apply some kind of reduction. The papers that apply a reduction have been used to produce the graphs that constitute the main content of this paper. Rock stiffness properties have been separated from those of streng

7、th in the analysis and this has illustrated interesting differences in their respective average reduction factors.METHODOLOGYThe review conducted has studied case histories and back analysis examples of numerical modelli

8、ng for a wide range of rock structures. Each reviewed paper has been databased in terms of laboratory measured rock properties and numerical modelling rock mass input properties plus other relevant quantitative data [1-3

9、7].The vast majority of papers have provided incomplete data either omitting key parameters or synthesizing parameters. Some papers have given laboratory and mass properties, and a few papers have explained the process b

10、y which laboratory properties have been adjusted to the rock mass by use of rock mass ratings. One can only conclude that this is related to the origin of the models or modellers, being from environments where materials

11、like steel have no scale effects. There would be few rock mechanics specialists who would not acknowledge that even the strongest rock types need some adjustment of their rock mass properties. The graphs and data provide

12、d in this paper have therefore concentrated on papers where reductions have been applied. A list of the most valid and relevant numerical papers is included at the end of the paper.RESULTSFigure 1 presents the Young'

13、s modulus results for laboratory tests plotted with those used in the model. Each case is numbered against its source. There is a simple trend in these data and if a straight line is fitted, model stiffness is on average

14、 0.469 of the laboratory stiffness (Fig. 2). The data can alternatively be plotted as reduction factors as in Fig. 3. Here a trend of increased reduction factors for low stiffness rock types becomes apparent. A number of

15、 very high reduction factors can also be seen for very low stiffness rocks. Figure 4 shows the uniaxial compressive 2000000 20000 40000 60000 80000 100000 120000400006000080000100000120000152714 1413 6216622 1631 1630212

16、1 21 211421 1432 142424321427619 2732 2316 21212130 303329Model E(MPa)Laboratory E(MPa)5000 10000 15000 20000 25000 005000100001500020000Laboratory E(MPa)Model E(MPa)1717 919 11 27 11 17 26 10 222220121711232323141423 12

17、15 14 24 2412 12 12 12 1251824141913 141171310241718 24247122413 191325 25 778102418117 10 1917 242217 24 17 17 1611 1014221710 1013Fig. 1. (a) Young's modulus from case histories for laboratory tests and numerical m

18、odelling input (range 0-120 GPa). (b)Young's modulus from cast histories for laboratory tests and numerical modelling input (range 0-28 GPa).2000000 20000 40000 60000 80000 100000 120000400006000080000100000120000Mod

19、el E(MPa)Laboratory E(MPa)Fig. 2. Young's modulus from case histories for laboratory tests and numerical modelling input.00 20000 40000 60000 80000 100000 120000Reduction Factor for Model E(MPa)Laboratory E(MPa)51015