Sains Malaysiana 50(2)(2021): 287-300

http://dx.doi.org/10.17576/jsm-2021-5002-02

Shear Failure Mechanism and Acoustic Emission Characteristics of Jointed Rock-Like Specimens

(Mekanisme Kegagalan Ricih dan Pencirian Pancaran Akustik pada Spesimen Seakan Batuan Berkekar)

YUXIN BAN¹, QIANG XIE^1,2*, XIANG FU³*, RINI ASNIDA ABDULLAH⁴ & JINGJING WANG¹

¹School of Civil Engineering, Chongqing University, 400044 Chongqing, People’s Republic of China

²Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, 400044 Chongqing, People’s Republic of China

³College of River and Ocean Engineering, Chongqing Jiaotong University, 400074 Chongqing, People’s Republic of China

⁴School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor Darul Takzim, Malaysia

Received: 7 March 2020/Accepted: 2 August 2020

ABSTRACT

Evidence indicate that the stability of rock mass is highly associated with the shear behaviours of jointed surfaces under the effect of in situ stress conditions. Understanding the shear failure mechanism of jointed surface has great significance for tunneling and drilling engineering. Direct shear tests were conducted on jointed rock-like specimens to investigate the influence of joint roughness and normal stress on shear failure characteristics. In the present study, regular triangular sawtooth was produced to simulate different asperities. Based on the direct shear test, the specimens exhibited four types of failure modes: damage tend to occur on the sawtooth tips under low normal stress; whereas damage occurred on a large scale under high normal stress; a localized region of the sawtooth was worn when the dilation angle was small; meanwhile the sawtooth tips or base were cut off when the dilation angle was large. In addition, Acoustic Emission (AE) technology was adopted to synchronously monitor the development of cracks during testing. Further attempt has been carried out to simulate the crack initiation, propagation and coalescence using Particle Flow Code (PFC). The numerical model has successfully verified and explained the crack behaviors determined by the shear failure mechanism in the physical test. Additionally, the irregular profile was introduced in the PFC, it was found that the failure behavior in sawtooth profile has established a good conclusion to fully understand the failure mechanism in the irregular profile. This work can provide some reference for evaluating the behavior of underground engineering composed of jointed rock masses during the shearing.

Keywords: Acoustic emission; failure mode; joint surface; particle flow code (PFC) simulation; shear failure mechanism

ABSTRAK

Bukti telah menunjukkan bahawa kestabilan jisim batuan berkaitan dengan sifat ricih bagi permukaan berkekar disebabkan oleh keadaan tekananin situ. Memahami mekanisme kegagalan ricih pada permukaan berkekar mempunyai kepentingan besar dalam kejuruteraan terowong dan penggerudian. Ujian ricih secara langsung telah dijalankan pada spesimen seakan batuan berkekar untuk mengkaji pengaruh kekasaran kekar dan tekanan normal pada ciri-ciri kegagalan ricih. Dalam uji kaji ini, gigi gergaji segitiga biasa dihasilkan untuk mensimulasikan asperiti yang berbeza. Hasil uji kaji ricih secara langsung menunjukkan empat jenis mod kegagalan: kerosakan cenderung berlaku pada hujung gigi-gergaji di bawah tekanan normal yang rendah; manakala kerosakan berlaku pada skala besar apabila dikenakan tekanan normal yang tinggi; kawasan setempat pada gigi gergaji didapati menjadi haus pada sudut perkembangan gigi gergaji yang kecil; sedangkan hujung atau pangkal gigi gergaji terpotong ketika sudut perkembangan gigi gergaji yang besar. Di samping itu, teknologi pancaran akustik (AE) juga digunakan untuk memantau perkembangan retakan semasa ujian. Selanjutnya, inisiasi, perambatan dan petautan retakan disimulasikan secara berangka menggunakan kod aliran zarah (PFC). Model berangka telah berjaya mengesah dan menjelaskan kelakuan retakan yang berlaku semasa kegagalan ricih pada uji kaji fizikal. Tambahan lagi, profil ketaksekataan telah diperkenalkan di dalam PFC dan didapati sifat kegagalan pada profil gigi gergaji telah menghasilkan kesimpulan yang baik dalam memahami mekanisme kegagalan ricih pada profil tak sekata. Hasil kajian ini akan dapat menjadi rujukan untuk menilai sifat kejuruteraan bawah tanah yang terdiri daripada jisim batuan berkekar semasa ricihan.

Kata kunci: Mekanisme kegagalan ricih; mod kegagalan; pancaran akustik; permukaan kekar; simulasi kod aliran zarah (PFC)

REFERENCES

Asadi, M.S., Rasouli, V. & Barla, G. 2012. A bonded particle model simulation of shear strength and asperity degradation for rough rock fractures. Rock Mechanics and Rock Engineering 45(5): 649-675.

Azinfar, M.J., Ghazvinian, A.H. & Nejati, H.R. 2019. Assessment of scale effect on 3D roughness parameters of fracture surfaces. European Journal of Environmental and Civil Engineering 23(1): 1-28.

Bahaaddini, M. 2017. Effect of boundary condition on the shear behaviour of rock joints in the direct shear test. Rock Mechanics and Rock Engineering 50(5): 1141-1155.

Ban, Y., Fu, X. & Xie, Q. 2020. Revealing the laminar shale microdamage mechanism considering the relationship between fracture geometrical morphology and acoustic emission power spectrum characteristics. Bulletin of Engineering Geology and the Environment 79(2): 1083-1096.

Bandis, S.C., Lumsden, A.C. & Barton, N.R. 1983. Fundamentals of rock joint deformation. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 20(6): 249-268.

Barton, N. 1973. Review of a new shear-strength criterion for rock joints. Engineering Geology 7: 287-332.

Barton, N., Bandis, S. & Bakhtar, K. 1985. Strength deformation and conductivity coupling of rock joints. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 20(3): 121-140.

Barton, N. & Choubey, V. 1977. The shear strength of rock joints in theory and practice. Rock Mechanics and Rock Engineering 10(1-2): 1-54.

Cai, M., Kaiser, P.K., Morioka, H., Minami, M., Maejima, T., Tasaka, Y. & Kurose, H. 2007. FLAC/PFC coupled numerical simulation of ae in large-scale underground excavations. International Journal of Rock Mechanics and Mining Sciences 44(4): 550-564.

Casagrande, D., Buzzi, O., Giacomini, A., Lambert, C. & Fenton, G. 2018. A new stochastic approach to predict peak and residual shear strength of natural rock discontinuities. Rock Mechanics and Rock Engineering 51(1): 69-99.

Cho, N., Martin, C.D. & Sego, D.C. 2008. Development of a shear zone in brittle rock subjected to direct shear. International Journal of Rock Mechanics and Mining Sciences 45(8): 1335-1346.

Cui, Y. 2019. Effect of joint type on the shear behavior of synthetic rock. Bulletin of Engineering Geology and the Environment 78(5): 3395-3412.

Fu, X., Xie, Q. & Liang, L. 2015. Comparison of the Kaiser effect in marble under tensile stresses between the Brazilian and bending tests. Bulletin of Engineering Geology and the Environment 74(2): 535-543.

Giwelli, A.A., Sakaguchi, K., Gumati, A. & Matsuki, K. 2014. Shear behaviour of fractured rock as a function of size and shear displacement. Geomechanics and Geoengineering 9(4) 253-264.

Grasselli, G., Wirth, J. & Egger, P. 2002. Quantitative three-dimensional description of a rough surface and parameter evolution with shearing. International Journal of Rock Mechanics and Mining Sciences 39(6): 789-800.

Gu, X.F., Seidel, J.P. & Haberfield, C.M. 2003. Direct shear test of sandstone-concrete joints. International Journal of Geomechanics 3(1): 21-33.

Hazzard, J.F., Collins, D.S., Pettitt, W.S. & Young, R.P. 2002. Simulation of unstable fault slip in granite using a bonded-particle model. Pure and Applied Geophysics 159(1): 221-245.

He, J., Pasternak, E. & Dyskin, A. 2019. Bridges outside fracture process zone: Their existence and effect. Engineering Fracture Mechanics 225: 106453.

Khazaei, C., Hazzard, J. & Chalaturnyk, R. 2015. Damage quantification of intact rocks using acoustic emission energies recorded during uniaxial compression test and discrete element modeling. Computers and Geotechnics 67: 94-102.

Liu, Z., Jia, J.S., Feng, W, Ma, F. & Zheng, C. 2017. Shear strength of cemented sand gravel and rock materials. Sains Malaysiana 46(11): 2101-2108.

Liu, X.R., Kou, M.M., Lu, Y.M. & Liu, Y.Q. 2018. An experimental investigation on the shear mechanism of fatigue damage in rock joints under pre-peak cyclic loading condition. International Journal of Fatigue 106: 175-184.

Meier, T., Rybacki, E., Backers, T. & Dresen, G. 2015. Influence of bedding angle on borehole stability: A laboratory investigation of transverse isotropic oil shale. Rock Mechanics and Rock Engineering 48(4): 1535-1546.

Mpalaskas, A.C., Matilzas, T.E., Van Hemelrijck, D., Papakitsos, G.S. & Aggelis, D.G. 2016. Acoustic emission monitoring of granite under bending and shear loading. Archives of Civil and Mechanical Engineering 16: 313-324.

Muralha, J., Grasselli, G., Tatone, B., Blümel, M., Chryssanthakis, P. & Yujing, J. 2014. ISRM suggested method for laboratory determination of the shear strength of rock joints: Revised version. Rock Mechanics and Rock Engineering 47: 291-302.

Oh, J. & Kim, G.W. 2010. Effect of opening on the shear behavior of a rock joint. Bulletin of Engineering Geology and the Environment 69(3): 389-395.

Park, J.W. & Song, J.J. 2009. Numerical simulation of a direct shear test on a rock joint using a bonded-particle model. International Journal of Rock Mechanics and Mining Sciences 46(8): 1315-1328.

Patton, F.D. 1966. Multiple modes of shear failure in rock. In Proceedings of the 1st Congress on International Society for Rock Mechanics Lisbon, Portugal. pp. 509-513.

Rafek, A.G. & Goh, T.L. 2014. Correlation of joint roughness coefficient (JRC) and peak friction angles of discontinuities of Malaysian schists. Sains Malaysiana 43(5): 751-756.

Rafek, A.G., Ong, B.C. & Goh, T.L. 2019. Geomechanical characterisation of rock mass and slope stability analysis at Laman Granview, Saujana Puchong, Selangor, Malaysia. Sains Malaysiana 48(4): 757-763.

Serasa, A.S., Lai, G.T., Rafek, A.G., Hussin, A., Khai Ern, L. & Mohamed, T.R. 2017. Peak friction angle estimation from joint roughness coefficient of discontinuities of limestone in Peninsular Malaysia. Sains Malaysiana 46(2): 181-188.

Shrivastava, A.K. & Rao, K.S. 2018. Physical modeling of shear behavior of infilled rock joints under CNL and CNS boundary conditions. Rock Mechanics and Rock Engineering 51(1): 101-118.

Wang, G., Zhang, Y., Jiang, Y., Liu, P., Guo, Y., Liu, J., Ma, M., Wang, K. & Wang, S. 2018. Shear behaviour and acoustic emission characteristics of bolted rock joints with different roughnesses. Rock Mechanics and Rock Engineering 51(6): 1885-1906.

Zhang, X., Lu, Y., Tang, J., Zhou, Z. & Liao, Y. 2017. Experimental study on fracture initiation and propagation in shale using supercritical carbon dioxide fracturing. Fuel 190: 370-378.

Zhou, X.P., Zhang, J.Z. & Wong, L.N.Y. 2018. Experimental study on the growth, coalescence and wrapping behaviors of 3D cross-embedded flaws under uniaxial compression. Rock Mechanics and Rock Engineering 51(5): 1379-1400.

*Corresponding author; email: xieqiang2000@163.com