外文翻译-应变率对盐岩机械性能的影响.doc

1、翻译部分英文原文Effect of strain rate on the mechanical properties of salt rock1. IntroductionSalt rock is a special material in rock engineering. With itsphysical properties of tight fabric and low permeability, as well as itsmechanical properties of low strength and ductility, it has become afavored mediu

2、m for waste disposal and oil and gas storage sinceearly in the last century, when it began to be thoroughly studied.More recently, achievements documented in the six conferences on the mechanical behavior of salt since 1984 and other publicationshave greatly increased knowledge of salt rock behavior

3、.As the strength of salt rock is somewhat low, generally the loading rate for compression tests is also slow. However, loading strain rate (e ) affects the mechanical properties of the salt rock.Studies have been carried out on many different rock types examining the effect of _e on rock strength an

4、d deformation characteristics. For example,e effects on dynamic tensile strength of Inada granite and Tage tuff were studied by Cho et al. 1; loading e values for the granite and the tuff were 4.2413.18 and 0.466.82/s, respectively. It was found that the dynamic tensile strength of the two rock type

5、s increased rapidly with e.After studying the porosity change of Mugla marble by heat treatment, compression tests under e values of 210- 55 10-7/s were conducted by Mahmutoglu 2. It was found that the compressive strength decreased sharply with strain rate decrease. For dry specimens, the percentag

6、e of the strength decrease is about 44% whereas the relative strength decrease for saturated specimens is much larger. It was suggested by Qi et al. 3 that the deformation and failure of rock under low strain rates were controlled mainly by thermally activated mechanisms. With strain rate increases,

7、 a phonon damping mechanism appears and gradually plays a dominant role in the deformation process. Li and Wang 4 studied the fracture toughness of marble under high loading rates using the Hopkinson bar method and found that the toughness increased significantly with the loading rate. Yang et al. 5

8、 carried out tests on limestone under different loading rates and found that the peak strength increased with the loading rate; at the same time, the strain at peak strength increased linearly with strain rate. He also found that the failure mode of the rock seldom changed with the loading rate.Ther

9、e are also many other studies 613 of the strain rate effect on mechanical properties of rocks; however, reports of strain rate effects on mechanical properties of salt rock are less well documented. To investigate this in the laboratory, we conducted uniaxial compression tests on salt rock (includin

10、g halite and thenardite) under loading e values of 2 10- 5,2 10- 4, and 2 10- 3/s. These results were generated as part of a more general investigation of the performance of gas storage operations in salt caverns.2. Sampling and methodology2.1. SamplesIn this paper, rock salt refers to rock with a d

11、ominant mineral component of halite (NaCl), whereas salt rock is a more general designation for all rocks with a dominant mineral component of highly soluble salts generally of evaporitic origin including NaCl, KCl, carnallite, bischofite, tachyhydrite, thenar-dite, mirabilite, glauberite, anhydrite

12、, and so on. Samples were cored from two evaporite deposits in Jiangsu Province, China. The evaporites are saline lake sediments of Tertiary age. One type of lithology is rock salt (halite), with the major deposit located 9001100 m deep; the other salt rock lithology is dominated by the mineral then

13、ardite (Na2SO4sodium sulfate), and is buried about 2000 m deep. Both are of evaporative crystallization origin and have the desired properties of fabric tightness and low permeability for fluid storage or waste disposal. Some silt fillings were occasionally found in the rock salt samples, and the in

14、tergranular insoluble silt content is less than 10% in weight; however, the thenardite samples were pure and homogeneous. Samples were transported to the Taiyuan University of Technology (TYUT) laboratory after careful packaging.In the laboratory, samples were processed according to ISRM suggested m

15、ethods. Nine cylindrical specimens with aspect ratios of 2:1 were eventually prepared, eight of which were successfully tested, six rock salt specimens and two thenardite specimens. For the six rock salt specimens, uniaxial compression tests with three different loading rates were conducted while th

16、e two thenardite specimens were tested with two lower loading rates. Generally, 35 specimens are suggested to be prepared for each test to guarantee reliability, but we were hampered by a lack of acceptable quality core. To compare loading rate differences with the limited specimen set, only two specimens for each test could realistically be assigned. The reason we nevertheless choose to present our test results here is that they were fo