Brazilian disc test study on tensile strength-weakening effect of high pre-loaded red sandstone under dynamic disturbance

Abstract

Tensile failure (spalling or slabbing) often occurs on the sidewall of deep tunnel, which is closely related to the coupled stress state of deep rock mass under high pre-static load and dynamic disturbance. To reveal the mechanism of rock tensile failure caused by this coupled stress mode, the Brazilian disc tests were carried on red sandstone under high pre-static load induced by dynamic disturbance. Based on the pure static tensile fracture load of red sandstone specimen, two static load levels (80% and 90% of the pure static tensile fracture load) were selected as the initial high pre-static loading state, and then the dynamic disturbance load was applied until the rock specimen was destroyed. The dynamic disturbance loading mode adopted a sinusoidal wave (sine-wave) load, and the loading wave amplitude was 20% and 10% of the pure static tensile fracture load, respectively. The dynamic disturbance frequencies were set to 1, 10, 20, 30, 40, and 50 Hz. The results show that the tensile failure strength and peak displacement of red sandstone specimens under coupled load actions are lower than those under pure static tensile load, and both parameters decrease significantly with the increase of dynamic disturbance frequency. With the increase of dynamic disturbance frequency, the decrease range of tensile strength of red sandstone increased from 3.3% to 9.4% when the pre-static load level is 80%. While when the pre-static load level is 90%, the decrease range will increase from 7.4% to 11.6%. This weakening effect of tensile strength shows that the deep surrounding rock is more likely to fail under the coupled load actions of pre-static load and dynamic disturbance. In this tensile failure mechanism of the deep surrounding rock, the stress environment of deep sidewall rock determines that the failure mode of rock is a tensile failure, the pre-static load level dominates the tensile failure strength of surrounding rock, and dynamic disturbance promotes the strength-weakening effect and affects the weakening range.

Keywords

spalling / deep surrounding rock / strength-weakening effect / pre-static load / dynamic disturbance / tensile failure / Brazilian disc test

References

[1] JiangQ, FengX-T, FanY-L, FanQ-X, LiuG-F, PeiS-F. In situ experimental investigation of basalt spalling in a large underground powerhouse cavern [J]. Tunnelling and Underground Space Technology, 2017, 68(10): 82-94

[2] FengX-T, XuH, QiuS-L, LiS-J, YangC-X, GuoH-S, ChengY, GaoY-H. In situ observation of rock spalling in the deep tunnels of the China Jinping underground laboratory (2400 m depth) [J]. Rock Mechanics and Rock Engineering, 2018, 51: 1193-1213

[3] HouZ-S, GongQ-M, SunZ-H. Primary failure types and their failure mechanisms of deep buried and intact marble at Jinping II Hydropower station [J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(4): 727-732

[4] DowdingC H, AnderssonC A. Potential for rock bursting and slabbing in deep caverns [J]. Engineering Geology, 1986, 22(3): 265-279

[5] DiederichsM S. The 2003 Canadian geotechnical colloquium: Mechanistic interpretation and practical application of damage and spalling prediction criteria for deep tunnelling [J]. Canadian Geotechnical Journal, 2007, 44(9): 1082-1116

[6] LuoY, GongF-Q, LiuD-Q, WangS-Y, SiX-F. Experimental simulation analysis of the process and failure characteristics of spalling in D-shaped tunnels under true-triaxial loading conditions [J]. Tunnelling and Underground Space Technology, 2019, 90: 42-61

[7] CaiM, KaiserP KRockburst support reference book-Volume I: Rockburst phenomenon and support characteristics [M], 2018, Ontario, Ming Innovation, Laurentian University Sudbury, 70

[8] LuoY, GongF-Q, LiX-B, WangS-Y. Experimental simulation investigation of the influence of depth on spalling characteristics in circular hard rock tunnel [J]. Jouranl Central South University, 2020, 27(3): 891-910

[9] WuW-X, GongF-Q, YangW-M. Experimental simulation study of spalling in deep rectangular tunnel with plastic fine grain marble [J]. Tunnelling and Underground Space Technology, 2020, 98: 103319

[10] GongF-Q, LuoY, LiX-B, SiX-F, TaoM. Experimental simulation investigation on rockburst induced by spalling failure in deep circular tunnels [J]. Tunnelling and Underground Space Technology, 2018, 81413-427

[11] HeM-C, LiuD-Q, GongW-L, WangC-C, KongJ, DuS, ZhangS. Development of a testing system for impact rockbursts [J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(9): 1729-1739

[12] GongF-Q, WuW-X, LiT-B, SiX-F. Experimental simulation and investigation of spalling failure of rectangular tunnel under different three-dimensional stress states [J]. International Journal of Rock Mechanics and Mining Sciences, 2019, 122: 104081

[13] ZhouH, LuJ-J, HuS-C, ZhangC-Q, XuR-C, MengF-Z. Influence of curvature radius of tunnels excavation section on slabbing of hard brittle rockmass under high stress [J]. Rock and Soil Mechanics, 2016, 31(1): 140-146

[14] GongF-Q, WuW-X, LiT-B. Simulation test of spalling failure of surrounding rock in rectangular tunnels with different height-to-width ratios [J]. Bulletin of Engineering Geology and the Environment, 2020, 793207-3219

[15] MartinC D, ChristianssonR. Estimating the potential for spalling around a deep nuclear waste repository in crystalline rock [J]. International Journal of Rock Mechanics and Mining Sciences, 2009, 46(2): 219-228

[16] LiX-BRock dynamics fundamentals and applications [M], 2014, Beijing, Science Press(in Chinese)

[17] AnderssonJ C, MartinC D, StilleH. The Äspö pillar stability experiment: Part II-rock mass response to coupled excavation-induced and thermal-induced stresses [J]. International Journal of Rock Mechanics and Mining Sciences, 2009, 46(5): 879-895

[18] CaiM, KaiserP K. In-situ rock spalling strength near excavation boundaries [J]. Rock Mechanics and Rock Engineering, 2014, 47: 659-675

[19] LiX-B, GongF-Q, TaoM, DongL-J, DuK, MaC-D, ZhouZ-L, YinT-B. Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining: A review [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2017, 9(4): 767-782

[20] SiX-F, GongF-Q. Strength-weakening effect and shear-tension failure mode transformation mechanism of rockburst for fine-grained granite under triaxial unloading compression conditions [J]. International Journal of Rock Mechanics and Mining Sciences, 2020, 131: 104347

[21] LiX-B, ZhouZ-L, LokT S, HongL, YinT-B. Innovative testing technique of rock subjected to coupled static and dynamic loads [J]. International Journal of Rock Mechanics and Mining Sciences, 2008, 45(5): 739-748

[22] GongF-Q, LiX-B, LiuX-L, ZhaoJ. Experimental study of dynamic characteristics of sandstone under one-dimensional coupled static and dynamic loads [J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29(10): 2076-2085

[23] GongF-Q, LiX-B, LiuX-L. Preliminary experimental study of characteristics of rock subjected to 3D coupled static and dynamic loads [J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(6): 1179-1190

[24] OrtleppW D. The behaviour of tunnels at great depth under large static and dynamic pressures [J]. Tunnelling and Underground Space Technology, 2001, 16(1): 41-48

[25] ZhangQ B, ZhaoJ. A review of dynamic experimental techniques and mechanical behaviour of rock materials [J]. Rock Mechanics and Rock Engineering, 2014, 47(4): 1411-1478

[26] MitelmanA, ElmoD. Analysis of tunnel support design to withstand spalling induced by blasting [J]. Tunnelling and Underground Space Technology, 2016, 51(6): 354-361

[27] LiX, LiX-F, ZhangQ-B, ZhaoJ. A numerical study of spalling and related rockburst under dynamic disturbance using a particle-based numerical manifold method (PNMM) [J]. Tunnelling and Underground Space Technology, 2018, 81438-449

[28] GongF-Q, ZhaoG-F. Dynamic indirect tensile strength of sandstone under different loading rates [J]. Rock Mechanics and Rock Engineering, 2014, 47(6): 2271-2278

[29] LiD-Y, WongL N Y. The Brazilian disc test for rock mechanics applications: Review and new insights [J]. Rock Mechanics and Rock Engineering, 2013, 46(2): 269-287

[30] GONG Feng-qiang, HU Jian. Energy dissipation characteristic of red sandstone in the dynamic Brazilian disc test with SHPB setup [J]. Advances in Civil Engineering, 2020(5): 1–10. DOI: https://doi.org/10.1155/2020/7160937.

[31] ISRM. Suggested methods for determining tensile strength of rock materials [J]. International Journal of Rock Mechanics and Mining Sciences, 1978, 15(3): 99-103

[32] D2936–08. Standard test method for direct tensile strength of intact rock core specimens [S]. Annual Book of ASTM Standards. ASTM International, West Conshohocken.

[33] D3967–08. Standard test method for splitting tensile strength of intact rock core specimens [S]. Annual Book of ASTM Standards, 2008, West Conshohocken, ASTM International

[34] ChenC-S, PanE, AmadeiB. Determination of deformability and tensile strength of anisotropic rock using Brazilian tests [J]. International Journal of Rock Mechanics and Mining Sciences, 1998, 35(1): 43-61

[35] ErarslanN, WilliamsD J. Experimental, numerical and analytical studies on tensile strength of rocks [J]. International Journal of Rock Mechanics and Mining Sciences, 2012, 49(1): 21-30

[36] MarkidesC F, KourkoulisS K. Naturally accepted boundary conditions for the Brazilian disc test and the corresponding stress field [J]. Rock Mechanics and Rock Engineering, 2013, 46(5): 959-980

[37] ZhuW C, BaiY, LiX B, NiuL L. Numerical simulation on rock failure under combined static and dynamic loading during SHPB tests [J]. International Journal of Impact Engineering, 2012, 49: 142-157

[38] GONG Feng-qiang, ZHANG Le, WANG Shan-yong. Loading rate effect of rock material with the direct tensile and three Brazilian disc tests [J]. Advances in Civil Engineering, 2019(2): 1–8. DOI: https://doi.org/10.1155/2019/6260351.

[39] GongF-Q, LiX-B, DongL-J. Algorithm to estimate tensile modulus of rock in disk impact splitting test [J]. Chinese Journal of Rock Mechanics and Engineering, 2013, 32(4): 705-713

[40] GongF-Q, ZhangL, LiX-B, LuoY. Experimental study on fracture behaviors of hard rock under dynamic disturbance with different pre-static loads [J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 36(8): 1841-1854

[41] GongF-Q, LuD-H, LiX-B, RaoQ-H, FuZ-T. Toughness increasing or decreasing effect of hard rock fracture with pre-static loading under dynamic disturbance [J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(9): 1905-1915