Abstract
Rock is a typical inhomogeneous material with a large number of flaws in different scales; the stress field of the rock in its elastic state consists of two parts: the elastic stress, which distributes uniformly in the entire region; and an additional stress, which only exists around the flaws. Theoretical expressions of the additional stress and local stress are derived based on the Maxwell model. Core disking which takes place under the condition that the axial stress is rapidly reduced while the confining pressure is kept unchanged is explained with a new method. Unloading duration’s effect on core disking is analyzed. A new criterion for core disking is presented based on attributing the core disking to the result of the exceedance of local tensile stress over the tensile strength. Based on our theoretical analysis and the conclusions from published resources, core disking is most likely to occur if the maximum principal stress is more than five to six times the tensile strength.
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Almeida, L.C.R., E.A. Vargas Jr., and R.P. Figueiredo (2006), Mechanical characterization of rock splitting planes in granitic rocks, Int. J. Rock Mech. Min. Sci. 43, 7, 1139–1145, DOI: 10.1016/j.ijrmms.2006.03.014.
Bauch, E., and C. Lempp (2004), Rock splitting in the surrounds of underground openings: an experimental approach using triaxial extension test. In: R. Hack, R. Azzam, and R. Charlier, Engineering Geology for Infrastructure Planning in Europe, Springer, Berlin, 244–254.
Corthesy, R., and M.H. Leite (2008), A strain-softening numerical model of core disking and damage, Int. J. Rock Mech. Min. 45, 3, 329–350, DOI: 10.1016/j.ijrmms.2007.05.005.
Ishida, T., and T. Saito (1995), Observation of core discing and in situ stress measurements; Stress criteria causing core disking, Rock Mech. Rock Eng. 28, 3, 167–182, DOI: 10.1007/BF01020150.
Jaeger, J.C., and N.G.W. Cook (1963), Pinching-off and disking of rocks, J. Geophys. Res. 68, 6, 1759–1765, DOI: 10.1029/JZ068i006p01759.
Lempp, C. H., and H.B. Muhlhaus (1985), Splitting and core disking in deep boreholes. In: 2nd Int. Symp. on Observation of the Continental Crust through Drilling, 94.
Li, Y.Y., and D.R. Schmitt (1998), Drilling-induced core fractures and in situ stress, J. Geophys. Res. 103, B3, 5225–5239, DOI: 10.1029/97JB02333.
Lim, S.S., and C.D. Martin (2010), Core discing and its relationship with stress magnitude for lac du bonnet granite, Int. J. Rock Mech. Min. 47, 2, 254–264, DOI: 10.1016/j.ijrmms.2009.11.007.
Matsuki, K., N. Kaga, T. Yokoyama, and N. Tsuda (2004), Determination of three dimensional in situ stress from core discing based on analysis of principle tensile stress, Int. J. Rock Mech. Min. Sci. 41, 7, 1167–1190, DOI: 10.1016/j.ijrmms.2004.05.002.
Obert, L., and D.E. Stephenson (1965), Stress conditions under which core disking occurs, Soc. Min. Eng. Trans. 232, 3, 227–235.
Qi, C.Z., and Q.H. Qian (2009), Basic Problems of Dynamic Deformation and Fracture of Rock Mass, Science Press, Beijing (in Chinese).
Rodionov, V.N., and I.A. Sizov (1982), Appearance of nonuniformity of the stressed state as a result of fracture of rocks, J. Min. Sci. 17, 4, 323–331, DOI: 10.1007/BF02497255.
Rodionov, V.N., and I.A. Sizov (1989), Model of a rigid body with dissipative structure for geomechanics, Soviet Min. 24, 6, 491–501, DOI: 10.1007/BF02498606.
Stacey, T.R. (1982), Contribution to the mechanism of core disking, J. S. Afr. Inst. Min. Metall. 82, 9, 269–274.
Zhu, W.-S., W.-M. Yang, X.-J. Li, X. Lu, and D.-J. Yu (2014), Study on splitting failure in rock masses by simulation test, site monitoring and energy model, Tunn. Undergr. Sp. Tech. 41, 152–164, DOI: 10.1016/j.tust.2013.12.007.
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Huang, H., Fan, P., Li, J. et al. A Theoretical Explanation for Rock Core Disking in Triaxial Unloading Test by Considering Local Tensile Stress. Acta Geophys. 64, 1430–1445 (2016). https://doi.org/10.1515/acgeo-2016-0068
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DOI: https://doi.org/10.1515/acgeo-2016-0068