Abstract
Roof falls in coal mines may occur within a few months to a few years after excavation. In this paper, we proposed the use of relaxation tests as a substitute for time-dependent tests. The relation between creep behavior and relaxation behavior was numerically investigated and demonstrates that the material assigned with creep model can show relaxation behavior. Then the relaxation model was developed by modifying the Burgers creep model. Numerical simulation of a relaxation test on a simulated rock model in 3DEC yielded results that were similar to theoretical prediction. A relaxation test was performed on two groups of specimens under varying load conditions. Results from the laboratory tests validated the approach of using relaxation test to determine time-dependent properties. Finally, time-dependent properties were investigated by performing relaxation tests at different stages of a complete stress–strain curve. The relaxation test during strain-softening was unsuccessful; however, the relaxation behavior at residual stage in post-failure region was more significant than that in pre-failure region and the sudden drop in stress indicated there was strength deterioration due to the accumulation of viscous strain.
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References
Aggson JR (1979) Design of room and pillar mining systems. In: First conference on ground control problems in the Illinois Coal Basin. Carbondale, Illinois
Chin H, Rogers JD (1987) Creep parameters of rocks on an engineering scale. Rock Mech 20:137–146
Dolinar DR, Mucho TP, Oyler DC, Pabtic J (2000) Utilizing the “advance-and-relieve” method to reduce horizontal stress effects on the mine roof, a case study. In: 19th Conference on ground control in mining. Morgantown, WV
Fakhimi A, Fairhurst C (1994) A model for the time-dependent behavior of rock. Int J Rock Mech Min Sci Geomech Abstr 31:117–126
Gadde MM, Peng SS (2005) Numerical simulation of cutter roof failure under weak roof conditions. In: SME annual meeting. Salt Lake City, UT, USA
Gao F, Stead D (2013) Discrete element modelling of cutter roof failure in coal mine roadways. Int J Coal Geol 116:158–171
Ghorbani M, Sharifzadeh M (2009) Long term stability assessment of Siah Bisheh powerhouse cavern based on displacement back analysis method. Tunn Undergr Space Technol 24:574–583
Goodman RE (1989) Introduction to rock mechanics, 2nd edn. Wiley, New York
Hudson A, Brown T (1972) Studying time-dependent effects in failued rock. In: The 14th U.S. symposium on Rock Mechanics (USRMS). University Park, Pennsylvania, pp 25–34
Iannacchione A, Coyle P, Prosser L et al (2004) The relationship of roof movement and strata-induced microseismic emissions to roof falls. In: 2004 SME annual meeting. Denver, pp 1–9
Itasca (2012) 3DEC
Ladanyi B, Melouki M (1993) Determination of creep properties of frozen soils. Can Geotech J 30:170–186
Li Y, Ghassemi A (2012) Creep Behavior of Barneet, Haynesville, And Marcellus Shale. In: 46th U.S. Rock Mechanics/Geomechanics Symposium. Chicago, IL, USA
Lorig L, Calderon Rojo A (2002) Modeling time-dependent slope deformation. In: ISRM international symposium-EUROCK 2002. Internatioanl Society for Rock Mechanics, Madeira, Portugal, pp 137–143
Malan DF, Vogler UW, Drescher K (1997) Time-dependent behaviour of hard rock in deep level gold mines. J South Afr Inst Min Metall 97(3):135–147
Mishra B, Verma P (2015) Uniaxial and triaxial single and multistage creep tests on coal-measure shale rocks. Int J Coal Geol 137:55–65
Peng S (1973) Time-dependent aspects of rock behavior as measured by a servocontrolled hydraulic testing machine. Int J Rock Mech Min Sci Geomech Abstr 10:235–246
Peng S, Podnieks ER (1972) Relaxation and the behavior of failed rock. Brain Res Rev 9:699–712
Price NJ (1964) A study of the time-strain behavior of coal-measure rocks. Int J Rock Mech Min Sci 1:277–303
Ray AK (2009) Influence of cutting sequence and time effects on cutters and roof falls in underground coal mine—numerical approach. West Virginia University, Morgantown
Spene J, Hult J (2001) Simple approximations for creep relaxation. Int J Mech Sci 15:741–755
Su W, Peng SS (1987) Cutter roof and its cause. Min Sci Technol 4:113–132
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Funding was provided by National Institute for Occupational Safety and Health.
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Xue, Y., Mishra, B. & Gao, D. Numerical and Laboratory Analysis of Relaxation Tests for Determining Time-Dependent Properties of Rock. Geotech Geol Eng 35, 615–629 (2017). https://doi.org/10.1007/s10706-016-0129-0
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DOI: https://doi.org/10.1007/s10706-016-0129-0