Influence of the saw-tooth angle of rock joints on the shear performance of 2G-NPR bolt

Abstract

The shear performance of bolts plays a crucial role in controlling rock mass stability, and the roughness of the joint surface is one of the main factors affecting the mechanical properties of anchored joints. The 2nd generation of negative Poisson ratio (2G-NPR) bolt is a new independently developed material characterized by high strength and toughness. However, the influence of joint surface roughness on its anchorage shear performance remains unexplored. This study involves preparing regular saw-tooth jointed rock masses and conducting laboratory shear comparison tests on unbolted samples, 2G-NPR bolts, and Q235 steel anchors. A three-dimensional finite element method, developed by the author, was employed for numerical simulations to analyze the influence of saw-tooth angles on the shear resistance of anchored bolts. The findings show that the anchorage of bolts enhances the shear strength and deformation of saw-tooth rock joints. The 2G-NPR bolts demonstrate superior performance in shear strength and deformation enhancement compared to Q235 steel anchors, including improved toughening and crack-arresting effects. Furthermore, the improvement of the shear strength and displacement of the bolt decreases with the increase of the joint saw-tooth angle. These findings provide a valuable test basis for the engineering application of 2G-NPR bolts in rock mass stabilization.

Keywords

jointed rock mass / shear resistance / bolt anchorage / 2G-NPR bolt / saw-tooth rock joint

References

[1] LinH, XiongZ-y, LiuT-y, et al.. Numerical simulations of the effect of bolt inclination on the shear strength of rock joints [J]. International Journal of Rock Mechanics and Mining Sciences, 2014, 66: 49-56.

[2] ChenY, CaoP, ZhouK-p, et al.. Relationship between loading angle and displacing angle in steel bolt shearing [J]. Transactions of Nonferrous Metals Society of China, 2017, 27(4): 876-882.

[3] JiangL-s, KongP, ShuJ-m, et al.. Numerical analysis of support designs based on a case study of a longwall entry [J]. Rock Mechanics and Rock Engineering, 2019, 52(9): 3373-3384.

[4] ZhengL-b, WangL-q, ZhuL-f, et al.. Analytical model of the shear behaviors of bolted rough joints based on the dilation effect and surface abrasion [J]. Engineering Geology, 2021, 294106399.

[5] LiG, LuoZ-y, WuC-z, et al.. Integrated early warning and reinforcement support system for soft rock tunnels: A novel approach utilizing catastrophe theory and energy transfer laws [J]. Tunnelling and Underground Space Technology, 2024, 150105869.

[6] LiG, ZhuC, LiuH-l, et al.. Energy balance support method in soft rock tunnel with energy absorbing anchor cable [J]. Tunnelling and Underground Space Technology, 2023, 141105380.

[7] LiC C. Field observations of rock bolts in high stress rock masses [J]. Rock Mechanics and Rock Engineering, 2010, 43(4): 491-496.

[8] LiuC H, LiY Z. Analytical study of the mechanical behavior of fully grouted bolts in bedding rock slopes [J]. Rock Mechanics and Rock Engineering, 2017, 50(9): 2413-2423.

[9] LiuC-h, LiY-Z. Research progress in bolting mechanism and theories of fully grouted bolts in jointed rock masses [J]. Chinese Journal of Rock Mechanics and Engineering, 2018, 37(8): 1856-1872(in Chinese)

[10] WuX-z, JiangY-j, WangG, et al.. Performance of a new yielding rock bolt under pull and shear loading conditions [J]. Rock Mechanics and Rock Engineering, 2019, 52(9): 3401-3412.

[11] MaS-q, ZhaoZ-y, ShangJ-L. An analytical model for shear behaviour of bolted rock joints [J]. International Journal of Rock Mechanics and Mining Sciences, 2019, 121104019.

[12] BjurstromS. Shear strength of hard rock joints reinforced by grouted untensioned bolts [C]. Proceedings of the 3rd International Congress on Rock Mechanics, 1974, Washington, DC. National Academy of Sciences. 119411992 (Part B)

[13] LiY-z, LiuC-H. Experimental study on the shear behavior of fully grouted bolts [J]. Construction and Building Materials, 2019, 223: 1123-1134.

[14] JalalifarH, AzizN, HadiM. The effect of surface profile, rock strength and pretension load on bending behaviour of fully grouted bolts [J]. Geotechnical & Geological Engineering, 2006, 24(5): 1203-1227.

[15] LiH-b, TanH-h, YuanW, et al.. Study on anchoring mechanism of shear direction perpendicular to rock bolt inclination [J]. Chinese Journal of Applied Mechanics, 2021, 38(5): 1995-2003

[16] LiuS G, HuangJ X, ZhangH. Study of shearing tests of bolted frictionless joints with different anchorage angles [J]. Chinese Journal of Underground Space and Engineering, 2022, 18(3): 824-831(in Chinese)

[17] ChenN, ZhangX-b, JiangQ-h, et al.. Shear behavior of rough rock joints reinforced by bolts [J]. International Journal of Geomechanics, 2018, 18104017130.

[18] WangL Q, ZhuL F, ZhengL B, et al.. Shear test of bolted joint rock masses considering joint roughness [J]. China Journal of Highway Transportation, 2021, 34(6): 38-47(in Chinese)

[19] ChenY. Experimental study and stress analysis of rock bolt anchorage performance [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2014, 6(5): 428-437.

[20] HeM-c, RenS-l, XuH-t, et al.. Experimental study on the shear performance of quasi-NPR steel bolted rock joints [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2023, 15(2): 350-362.

[21] LiX-w, AzizN, MirzaghorbanaliA, et al.. Behavior of fiber glass bolts, rock bolts and cable bolts in shear [J]. Rock Mechanics and Rock Engineering, 2016, 49(7): 2723-2735.

[22] ChenY, LiC C. Performance of fully encapsulated rebar bolts and D-bolts under combined pull-and-shear loading [J]. Tunnelling and Underground Space Technology, 2015, 45: 99-106.

[23] GrasselliG. 3D behaviour of bolted rock joints: Experimental and numerical study [J]. International Journal of Rock Mechanics and Mining Sciences, 2005, 42(1): 13-24.

[24] ZhangY-c, JiangY-j, WangZ, et al.. Anchorage effect of bolt on en-echelon fractures: A comparison between energy-absorbing bolt and conventional rigid bolt [J]. Engineering Failure Analysis, 2022, 137106256.

[25] WuX-z, JiangY-j, GongB, et al.. Shear performance of rock joint reinforced by fully encapsulated rock bolt under cyclic loading condition [J]. Rock Mechanics and Rock Engineering, 2019, 52(8): 2681-2690.

[26] CuiG-j, ZhangC-q, ChenJ-l, et al.. Effect of bolt inclination angle on shear behavior of bolted joints under CNL and CNS conditions [J]. Journal of Central South University, 2020, 27(3): 937-950.

[27] WuX-z, JiangY-j, LiB. Influence of joint roughness on the shear behaviour of fully encapsulated rock bolt [J]. Rock Mechanics and Rock Engineering, 2018, 51(3): 953-959.

[28] WangG, ZhangY-z, JiangY-j, et al.. Shear behaviour and acoustic emission characteristics of bolted rock joints with different roughnesses [J]. Rock Mechanics and Rock Engineering, 2018, 51(6): 1885-1906.

[29] ZhangS B, WangC S, WangG, et al.. Experimental study on the shear behaviors of bolted rock joints reinforced with BFRP bars [J]. Chinese Journal of Rock Mechanics and Engineering, 2022, 41(4): 712-724(in Chinese)

[30] HE M C, XIA M, GUO H Y. NPR anchor rod steel material and production method: CN, ZL201810503966.5 [P]. (in Chinese)

[31] HeM-c, WangQ, WuQ-Y. Innovation and future of mining rock mechanics [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2021, 13(1): 1-21.

[32] GuT-y, JiaL-j, ChenB, et al.. Unified full-range plasticity till fracture of meta steel and structural steels [J]. Engineering Fracture Mechanics, 2021, 253107869.

[33] TangJ, HeM-c, QiaoY-f, et al.. Tensile behavior of a novel high-strength and high-toughness steel at strain rates from 0.1 s⁻¹ to 1000 s⁻¹ [J]. Construction and Building Materials, 2021, 304124606.

[34] HeM-c, RenS-l, GuoL-j, et al.. Experimental study on influence of host rock strength on shear performance of micro-NPR steel bolted rock joints [J]. International Journal of Rock Mechanics and Mining Sciences, 2022, 159105236.

[35] BelemT, Homand-EtienneF, SouleyM. Quantitative parameters for rock joint surface roughness [J]. Rock Mechanics and Rock Engineering, 2000, 33(4): 217-242.

[36] LiuX R, ZengX, XuB, et al.. Shear mechanical behavior of rock with through-type saw-tooth joints [J]. Journal of Civil and Environmental Engineering, 2023, 45(5): 1-9(in Chinese)

[37] HeD L, YangW J, LinH, et al.. Numerical analysis for direct shear test of bolted joint based on particle flow code [J]. Journal of Engineering Geology, 2019, 27(2): 302-310(in Chinese)

[38] SaadatM, TaheriA. Effect of contributing parameters on the behaviour of a bolted rock joint subjected to combined pull-and-shear loading: A DEM approach [J]. Rock Mechanics and Rock Engineering, 2020, 53(1): 383-409.

[39] ChenY-f, LinH, XieS-j, et al.. Effect of joint microcharacteristics on macroshear behavior of single-bolted rock joints by the numerical modelling with PFC [J]. Environmental Earth Sciences, 2022, 8110276.

[40] TahmasebiniaF, ZhangC-g, CanbulatI, et al.. Numerical and analytical simulation of the structural behaviour of fully grouted cable bolts under impulsive loading [J]. International Journal of Mining Science and Technology, 2018, 28(5): 807-811.

[41] JiangY-j, ZhangS-h, LuanH-j, et al.. Numerical modelling of the performance of bolted rough joint subjected to shear load [J]. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2022, 85140.

[42] SunB-j, LiuQ-w, LiW-t, et al.. Numerical implementation of rock bolts with yield and fracture behaviour under tensile-shear load [J]. Engineering Failure Analysis, 2022, 139106462.

[43] RenS-l, TaoZ-g, HeM-c, et al.. Numerical simulation study on shear resistance of anchorage joints considering tensile-shear fracture criterion of 2G-NPR bolt [J]. International Journal of Coal Science & Technology, 2023, 10158.

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Central South University