Advertisement

Geotechnical and Geological Engineering

, Volume 28, Issue 3, pp 241–249 | Cite as

Characterization of a Sedimentary Soft Rock by a Small In-Situ Triaxial Test

  • Abbas Taheri
  • Kazuo Tani
Original Paper

Abstract

To measure the shear strength and deformability of a sedimentary soft rock, a small down-hole in-situ triaxial testing method is developed. The apparatus consists of a triaxial cell and an axial loading device which enables testing at any depth. In this method, a columnar specimen of diameter 90 mm and 285 mm height can be sheared at the bottom of a drill hole. A series of tests were conducted at a 50 m deep experimental cavern. The test gallery is contained in mudstone with some inter-bedded thin sand layers. The tests were done in three different depths in a borehole by a multiple-step loading method. The new testing method was successful to measure stress–strain relation of rock mass. The test results demonstrated that the multiple-step loading method is acceptable in mudstone formation, if an appropriate criterion for load reversal is selected to recognize the instant of failure by stress–strain relation during loading. In addition, different results for mechanical properties of mudstone rock mass were observed in the specimens contained sand layers. It is also concluded that, the same loading method is not successful if a sand layer is located in the middle of the specimen due to large damage induced in early stages of loading.

Keywords

In-situ test Triaxial test Shear strength Stiffness Mudstone Multiple-step loading 

References

  1. Tatsuoka F, Hayano K, Koseki J (2003) Strength and deformation characteristics of sedimentary soft rock in the Tokyo metropolitan area, In: Tan et al (ed) Proceedings of characterization and engineering properties of natural soils, Swets and Zeitlinger, Lisse, 2003Google Scholar
  2. Liang W, Yang C, Zhao Y, Dusseault MB, Liu J (2007) Experimental investigation of mechanical properties of bedded salt rock. Int J Rock Mech Min Sci 44:400–411. doi: 10.1016/j.ijrmms.2006.09.007 CrossRefGoogle Scholar
  3. Athanasopoulos GA (1995) Utilization of sample disturbance for dating a marl deposit. Geotech Geol Eng 13(2):93–104. doi: 10.1007/BF00421875 CrossRefGoogle Scholar
  4. Tani K (1999) Proposal of new in-situ test methods to investigate strength and deformation characteristics of rock masses. In: Proceeding of 2nd international symposium on pre-failure deformation of geomaterials, Torino, ItalyGoogle Scholar
  5. Tani K, Nazaki T, Kaneko S (2003) Down-hole triaxial test to measure average stress–strain relationship of rock mass. Soils Found 43(5):53–62Google Scholar
  6. Taheri A, Tani K (2007) Improvements in down-hole in-situ triaxial testing system. In: Proceeding of 42nd Japan geotechnical society conference, Nagoya, JapanGoogle Scholar
  7. Taheri A, Tani K (2008) Characterization of mudstone in a deep underground cavern—comparison of full-scale behavior and field and laboratory tests. 3rd international site characterization conference, Taipei, Taiwan, p 7Google Scholar
  8. Aoki T, Fujikawa T, Ochi K (1991) Characterization of discontinuities in mudstone rock masses (Dotan), In: Proceedings of 4th international conference on underground space and earth sheltered buildings, Tokyo, JapanGoogle Scholar
  9. Goto S, Tatsuoka F, Shibuya S, Kim YS, Sato T (1991) A simple gauge for local small strain measurements in the laboratory. Soils Found 31(1):169–180Google Scholar
  10. Kovari K, Tisa A (1975) Multiple failure state and strain controlled triaxial tests. Rock Mech 7:17–33. doi: 10.1007/BF01239232 CrossRefGoogle Scholar
  11. Kovari K, Tisa A, Einstein HH, Franklin JA (1983) Suggested methods for determining the strength of rock material in triaxial compression: revised version. Int J Rock Mech Min Sci 20(6):283–290Google Scholar
  12. Kim MM, Ko HY (1979) Multistage triaxial testing of rocks. Geotech Test J 2:98–105CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Geotechnical Lab, Department of Civil EngineeringYokohama National UniversityYokohamaJapan

Personalised recommendations