DETERMINATION OF STATIC ELASTIC MODULUS AND POISSON’S RATIO OF ROCKS UNDER WATER CONTENT VARIATION
The analysis is focused on elastic properties (elasticity modulus, Poisson’s ratio) of wall rocks at diamond deposits in Yakutia. Uniaxial compression tests involved air-dry and wet specimens of rocks (limestone, siltstone). The research objective was to find observable regular patterns in the change of elastic properties of the specimens with the change in their state characterized by excess moisture content (wet as against air-dry). The method of recording of small reversible strains in a specimen is based on the fact that longitudinal and transverse strains are measured in a specimen under loading within a certain range when deformation is linearly elastic and results in no irreversible structural changes. This method allowed complete testing cycle using a single specimen and eliminated errors due to different properties of specimens. A specimen was placed in water until complete saturation. Testing was carried out in the course of natural drying of the specimen, in certain time intervals, and the elastic modulus and Poisson’s ratio were evaluated based on the resultant deformation diagrams. The test cycle was 28 day per specimen. It is found that the change in the elastic properties as a function of water saturation has essentially nonlinear character. When moisture content of a specimen was 20% of the maximum level (in water-saturated state), the properties of siltstone and limestone changed more than by 50% and 90%, respectively, of the maximum change reached in water-saturated state as against air-dry state.
The work is executed at financial support of Russian Foundation for Basic Research (project No. 15-45-05014).
Rock, compression, elastic modulus, Poisson’s ratio, water content.
Issue number: 7
UDK: 622.023.25: 539.32
Authors: Suknev S. V.
About authors: Suknev S. V., Doctor of Engineering Sciences, Head of Laboratory,
e-mail: email@example.com, N. V. Chersky Institute of Mining of the North,
Siberian Branch of Russian Academy of Sciences, 677980, Yakutsk, Russia.
REFERENCES: 1. Kodama J., Goto T., Fujii Y., Hagan P. The effects of water content, temperature and loading rate on strength and failure process of frozen rocks. Int. J. Rock Mech. Min. Sci. 2013. Vol. 62. P. 1–13.
2. Porody gornye. Metod opredeleniya deformatsionnykh kharakteristik pri odnoosnom szhatii. GOST 28985-91 (Rocks. Method for determination of deformation characteristics under uniaxial compression. State Standart 28985-91), Moscow, IPK Izdatel’stvo standartov, 2004, 11 p.
3. Martin C. D., Chandler N. A. The progressive fracture of Lac du Bonnet granite. Int. J. Rock Mech. Min. Sci. & Geomech. Abstr. 1994. Vol. 31, No. 6. P. 643–659.
4. Eberhardt E., Stead D., Stimpson B., Read R. S. Identifying crack initiation and propogation tresholds in brittle rock. Can. Geotech. J. 1998. Vol. 35, No. 2. P. 222–233.
5. Hakala M., Kuula H., Hudson J. A. Estimating the transversely isotropic elastic intact rock properties for in situ stress measurement data reduction: A case study of the Olkiluoto mica gneiss, Finland. Int. J. Rock Mech. Min. Sci. 2007. Vol. 44, No. 1. P. 14–46.
6. Suknev S. V. Gornyy informatsionno-analiticheskiy byulleten’. 2013, no 8, pp. 101–105.
7. Porody gornye. Metody opredeleniya predela prochnosti pri odnoosnom szhatii. GOST 21153.2-84 (Rocks. Methods for determination of axial compression strength. State Standart 21153.2-84), Moscow, IPK Izdatel’stvo standartov, 2001, 8 p.
8. Suknev S. V. Gornyy informatsionno-analiticheskiy byulleten’. 2012, no 12, pp. 22–27.
9. Suknev S. V. Gornyy informatsionno-analiticheskiy byulleten’. 2013, no 8, pp. 97–100.