On the overload phenomenon in dynamic Brazilian disk experiments of rocks

XIA Kaiwen; YU Yuchao; WANG Shuai; WU Bangbiao; XU Ying; CAI Yingpeng

doi:10.11883/bzycj-2020-0369

Volume 41 Issue 4

Apr. 2021

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XIA Kaiwen, YU Yuchao, WANG Shuai, WU Bangbiao, XU Ying, CAI Yingpeng. On the overload phenomenon in dynamic Brazilian disk experiments of rocks[J]. Explosion And Shock Waves, 2021, 41(4): 041403. doi: 10.11883/bzycj-2020-0369

Citation:

XIA Kaiwen, YU Yuchao, WANG Shuai, WU Bangbiao, XU Ying, CAI Yingpeng. On the overload phenomenon in dynamic Brazilian disk experiments of rocks[J]. Explosion And Shock Waves, 2021, 41(4): 041403. doi: 10.11883/bzycj-2020-0369

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On the overload phenomenon in dynamic Brazilian disk experiments of rocks

doi: 10.11883/bzycj-2020-0369

XIA Kaiwen^{1, 2
,},
YU Yuchao^{1, 2},
WANG Shuai^{1, 2},
WU Bangbiao^{1, 2
,
,},
XU Ying^{1, 2},
CAI Yingpeng^{1, 2}

1.
State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300372, China
2.
School of Civil Engineering, Tianjin University, Tianjin 300350, China

Received Date: 2020-10-09
Rev Recd Date: 2020-11-19

Available Online: 2021-03-05

Publish Date: 2021-04-14

Abstract

Abstract

The Brazilian disk (BD) test is one of the testing methods suggested by the International Society for Rock Mechanics and Rock Engineering (ISRM) for determining the static tensile strength of rocks. Meanwhile, it is also the only method suggested by ISRM to determine the dynamic tensile strength of rock materials. However, it is worth noting that both static and dynamic tensile strengths of rocks tend to be overestimated using the BD specimen. This can be partially attributed to the overload phenomenon, which is particularly pronounced in dynamic BD tests. In this manuscript, the physical interpretation of the load used in BD test is revised based on the Griffith criterion. To systemically investigate the mechanism and the loading rate dependence of the overload phenomenon for rock materials, the dynamic BD tests under different loading rates were conducted using split Hopkinson pressure bar (SHPB) system. A strain gauge was attached 5 mm off the disk center to detect the failure onset. Then the transmitted wave signal was recorded and processed according to the distance of wave propagation on the transmitted bar and the specimen. The so-called nominal tensile strength and the real tensile strength were obtained through analyzing. The overload phenomenon was then quantitatively evaluated using the pre-defined overload ratio. Additionally, numerical simulations were carried out through the particle flow code (PFC) to observe the failure processes of the disk specimens in microscale. The loading rate dependency was introduced to revise the micro parameters to get a better simulation result. The overload phenomenon and the overload ratio were observed and calculated. The results show that: (1) the overload phenomenon of tensile strength can be obviously observed in the dynamic BD tests, and the overload ratio of the tensile strength logarithmically increases with the loading rate. (2) The overload phenomenon inspected by numerical simulation agrees well with the experimental observation. These results have demonstrated that the overload phenomenon does exist in dynamic BD tests. Its intrinsic mechanism is related to the geometry of specimen and the principle of the testing method based on the experimental and numerical tests. The overload ratio can reach 40% under a high loading rate. It is thus necessary to correct the result from the dynamic BD test to determine the real dynamic tensile strength using the method proposed in this work.
- dynamic BD test,
- overload phenomenon,
- tensile strength,
- loading rate dependency,
- particle flow code analysis

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References(20)

References

[1]	章奇锋, 周春宏, 周辉, 等. 锦屏Ⅱ水电站辅助洞岩爆灾害评价及对策研究 [J]. 岩土力学, 2009, 30(S2): 422–426, 445. DOI: 10.16285/j.rsm.2009.s2.045. ZHANG Q F, ZHOU C H, ZHOU H, et al. Research on rock burst estimation and control measures for auxiliary tunnels in Jinping Ⅱ hydropower station [J]. Rock and Soil Mechanics, 2009, 30(S2): 422–426, 445. DOI: 10.16285/j.rsm.2009.s2.045.
[2]	ZHOU Y X, XIA K, LI X B, et al. Suggested methods for determining the dynamic strength parameters and Mode-I fracture toughness of rock materials [M]// ULUSAY R. The ISRM Suggested Methods for Rock Characterization, Testing and Monitoring: 2007-2014. Cham: Springer International Publishing, 2015: 35−44. DOI: 10.1007/978-3-319-07713-0_3.
[3]	ZHANG Q B, ZHAO J. A review of dynamic experimental techniques and mechanical behaviour of rock materials [J]. Rock Mechanics and Rock Engineering, 2014, 47(4): 1411–1478. DOI: 10.1007/s00603-013-0463-y.
[4]	ULUSAY R, AND HUDSON J A. Suggested methods for determining tensile strength of rock materials [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1978, 15(3): 99–103. DOI: 10.1016/0148-9062(78)90003-7.
[5]	HUDSON J A. Tensile strength and the ring test [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1969, 6(1): 91–97. DOI: 10.1016/0148-9062(69)90029-1.
[6]	ZHAO J, LI H B. Experimental determination of dynamic tensile properties of a granite [J]. International Journal of Rock Mechanics and Mining Sciences, 2000, 37(5): 861–866. DOI: 10.1016/S1365-1609(00)00015-0.
[7]	LUONG M P. Tensile and shear strengths of concrete and rock [J]. Engineering Fracture Mechanics, 1990, 35(1−3): 127–135. DOI: 10.1016/0013-7944(90)90190-R.
[8]	HONDROS G. The evaluation of Poisson’s ratio and the modules of materials of a low tensile resistance by the Brazilian (indirect tensile) test with particular reference to concrete [J]. Australian Journal of Applied Science, 1959, 10: 243–268.
[9]	ROSS C A, THOMPSON P Y, TEDESCO J W. Split-hopkinson pressure-bar tests on concrete and mortar in tension and compression [J]. Materials Journal, 1989, 86(5): 475–481. DOI: 10.14359/2065.
[10]	陈登平, 王永刚, 贺红亮, 等. 强角闪石化橄榄二辉岩的动态拉伸强度实验研究 [J]. 爆炸与冲击, 2005, 25(6): 559–563. DOI: 10.11883/1001-1455(2005)06-0559-05. CHEN D P, WANG Y G, HE H L, et al. Dynamic tensile strength of amphibolized olivine websterite (AOW) rock [J]. Explosion and Shock Waves, 2005, 25(6): 559–563. DOI: 10.11883/1001-1455(2005)06-0559-05.
[11]	XIA K W, YAO W, WU B B. Dynamic rock tensile strengths of Laurentian granite: experimental observation and micromechanical model [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2017, 9(1): 116–124. DOI: 10.1016/j.jrmge.2016.08.007.
[12]	WU B B, CHEN R, XIA K W. Dynamic tensile failure of rocks under static pre-tension [J]. International Journal of Rock Mechanics and Mining Sciences, 2015, 80: 12–18. DOI: 10.1016/j.ijrmms.2015.09.003.
[13]	MELLOR M, HAWKES I. Measurement of tensile strength by diametral compression of discs and annuli [J]. Engineering Geology, 1971, 5(3): 173–225. DOI: 10.1016/0013-7952(71)90001-9.
[14]	FREW D J, FORRESTAL M J, CHEN W. Pulse shaping techniques for testing elastic-plastic materials with a split Hopkinson pressure bar [J]. Experimental Mechanics, 2005, 45(2): 186. DOI: 10.1007/BF02428192.
[15]	李夕兵, 古德生, 赖海辉. 冲击载荷下岩石动态应力-应变全图测试中的合理加载波形 [J]. 爆炸与冲击, 1993, 13(2): 125–130. LI X B, GU D S, LAI H H. On the reasonable loading stress waveforms determined by dynamic stress-strain curves of rocks by SHPB [J]. Explosion and Shock Waves, 1993, 13(2): 125–130.
[16]	DAI F, HUANG S, XIA K W, et al. Some fundamental issues in dynamic compression and tension tests of rocks using split hopkinson pressure bar [J]. Rock Mechanics and Rock Engineering, 2010, 43(6): 657–666. DOI: 10.1007/s00603-010-0091-8.
[17]	JIANG F C, LIU R T, ZHANG X X, et al. Evaluation of dynamic fracture toughness K_Id by Hopkinson pressure bar loaded instrumented Charpy impact test [J]. Engineering Fracture Mechanics, 2004, 71(3): 279–287. DOI: 10.1016/S0013-7944(03)00139-5.
[18]	SHI C, YANG W K, YANG J X, et al. Calibration of micro-scaled mechanical parameters of granite based on a bonded-particle model with 2D particle flow code [J]. Granular Matter, 2019, 21(2): 38. DOI: 10.1007/s10035-019-0889-3.
[19]	YANG J X, SHI C, YANG W K, et al. Numerical simulation of column charge explosive in rock masses with particle flow code [J]. Granular Matter, 2019, 21(4): 96. DOI: 10.1007/s10035-019-0950-2.
[20]	ZHOU Z L, LI X B, ZOU Y, et al. Dynamic brazilian tests of granite under coupled static and dynamic loads [J]. Rock Mechanics and Rock Engineering, 2014, 47(2): 495–505. DOI: 10.1007/s00603-013-0441-4.