Document Type : Original Research Paper

Authors

1 Department of Mining Engineering, Hamedan University of Technology, Hamedan, Iran.

2 Department of Mining Engineering, Higher Education Complex of Zarand, Shahid Bahonar University of Kerman, Kerman, Iran.

3 School of Civil Engineering and Transportation, North China University of Water Resources and Electric Power, Zhengzhou, 450046, China., Email: fujinwei1987@126.com

4 Department of Mine Exploitation Engineering, Faculty of Mining and Metallurgy, Institute of Engineering, Yazd University, Yazd, Iran.

5 Department of Geology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran

10.22044/jme.2026.17499.3478

Abstract

Determining the tensile strength of brittle, layered materials, including layered rocks and cracked concrete, is difficult when using commonly adopted indirect loading configurations that do not induce pure tensile conditions. Therefore, obtaining tensile strength through direct experimental quantification is crucial for such materials, particularly when examining crack onset and subsequent crack growth in the vicinity of crack tips. The present research proposes a novel direct tension-based testing framework designed to deliver more reliable strength characterization of layered quasi-brittle materials, while simultaneously enabling a detailed assessment of fracture initiation and propagation mechanisms. The testing apparatus consists of a steel beam with a load converter that serves as both the loading fixture and the load cell. A pre-holed layered sample is securely positioned at the center of the apparatus using a strong metal plate, while strain gauges on both sides capture critical data on the specimen's tensile behavior. Significantly, the apparatus can detect and quantify asymmetric failure within the specimen, offering a detailed understanding of crack formation and failure patterns. The design, calibration protocols, and empirical test results are thoroughly detailed and analyzed. Additionally, this study employs 3D PFC modeling to clarify the breakage mechanisms in various layer configurations, thereby enhancing the accuracy of tensile strength measurements. The numerical modeling results demonstrate that increasing the thickness of the hard layer leads to a nonlinear increase in the specimen's resistance. Furthermore, at a constant hard layer thickness, increasing the number of hard layers results in a decrease in the model's resistance.

Keywords

Main Subjects

[1]. Cho, J., Kim, H., Jeon, S., & Min, K. (2012). Deformation and strength anisotropy of Asan gneiss, Boryeong shale, and Yeoncheon schist. International Journal of Rock Mechanics and Mining Sciences, 50, 158–169.
[2]. Bi, J., Du, C., Zhao, Z. Y., Wang, C., Lian, S., & Xiong, X. (2023). Characterization of shear behavior and damage mechanism of periodic thermal loading sandstone based on NMR technique. Engineering Geology, 325, 107272.
[3]. Liang, X., Tang, S., Tang, C., Hu, L., & Chen, F. (2023). Influence of water on the mechanical properties and failure behaviors of sandstone under triaxial compression. Rock Mechanics and Rock Engineering, 56, 1131–1162.
[4]. Zhao, C., Liu, J., Xu, D., Zhang, L., Lyu, C., & Ren, Y. (2023). Investigation on mechanical properties, AE characteristics, and failure modes of Longmaxi Formation shale in Changning, Sichuan Basin, China. Rock Mechanics and Rock Engineering, 56, 1239–1272.
[5]. Fan, W., Zhang, J., Yang, Y., Fang, K., Wu, S., & Xing, Y. (2023). Effects of layering angle and prestress on dynamic load energy conversion and damage mechanism of sandstone. Processes, 11(9), 2641.
[6]. Lisjak, A., Tatone, B. S. A., Grasselli, G., & Vietor, T. (2014). Numerical modelling of the anisotropic mechanical behavior of Opalinus Clay at the laboratory-scale using FEM/DEM. Rock Mechanics and Rock Engineering, 47, 187–206.
[7]. Heng, S., Guo, Y., Yang, C., Daemen, J. J. K., & Li, Z. (2015). Experimental and theoretical study of the anisotropic properties of shale. International Journal of Rock Mechanics and Mining Sciences, 74, 58–68.
[8]. Li, Y., Zhou, H., Zhu, W., Li, S., & Liu, J. (2015). Numerical study on crack propagation in brittle jointed rock mass influenced by fracture water pressure. Materials, 8(6), 3364–3376.
[9]. Li, Y., Wang, H., Zhu, W., Li, S., & Liu, J. (2015). Structural stability monitoring of a physical model test on an underground cavern group during deep excavations using FBG sensors. Sensors, 15(9), 21696–21709.
[10]. Wang, Y., Li, X., & Zhang, B. (2016). Numerical modeling of variable fluid injection-rate modes on fracturing network evolution in naturally fractured formations. Energies, 9(6), 414.
[11]. Wang, Y., Li, X., Hu, R., Ma, C., Zhao, Z., & Zhang, B. (2016). Numerical evaluation and optimization of multiple hydraulically fractured parameters using a flow-stress-damage coupled approach. Energies, 9(5), 325.
[12]. Wang, Y., & Li, C. H. (2017). Investigation of the effect of cemented fractures on fracturing network propagation in model block with discrete orthogonal fractures. Rock Mechanics and Rock Engineering, 50, 1851–1862.
[13]. Li, Y., Li, C., Zhang, L., Zhu, W., Li, S., & Liu, J. (2017). An experimental investigation on mechanical property and anchorage effect of bolted jointed rock mass. Geosciences Journal, 21, 253–265.
[14]. Li, Y., Zhou, H., Dong, Z., Zhu, W., Li, S., & Wang, S. (2018). Numerical investigations on stability evaluation of a jointed rock slope during excavation using an optimized DDARF method. Geomechanics and Engineering, 14(3), 271–281.
[15]. Wang, Y., Tan, W. H., Liu, D. Q., Hou, Z. Q., & Li, C. H. (2019). On anisotropic fracture evolution and energy mechanism during marble failure under uniaxial deformation. Rock Mechanics and Rock Engineering, 52, 3567–3583.
[16]. Suo, Y., Chen, Z., Rahman, S. S., et al. (2020). Experimental and numerical investigation of the effect of bedding layer orientation on fracture toughness of shale rocks. Rock Mechanics and Rock Engineering, 53, 3625–3635.
[17]. Li, K., Yin, Z. Y., Han, D., et al. (2021). Size effect and anisotropy in a transversely isotropic rock under compressive conditions. Rock Mechanics and Rock Engineering, 54, 4639–4662.
[18]. Ren, L., Xie, H. P., Sun, X., Zhang, R., Li, C. B., Xie, J., & Zhang, Z. T. (2021). Characterization of anisotropic fracture properties of Silurian Longmaxi shale. Rock Mechanics and Rock Engineering, 54, 665–678.
[19]. Golewski, G. L. (2023a). Examination of water absorption of low volume fly ash concrete (LVFAC) under water immersion conditions. Materials Research Express, 10(8).
[20]. Golewski, G. L. (2023b). Assessing of water absorption on concrete composites containing fly ash up to 30% in regards to structures completely immersed in water. Case Studies in Construction Materials, 19, e02337.
[21]. Golewski, G. L. (2023c). Effect of coarse aggregate grading on mechanical parameters and fracture toughness of limestone concrete. Infrastructures, 8(8), 117.
[22]. Golewski, G. L. (2024). Enhancement fracture behavior of sustainable cementitious composites using synergy between fly ash (FA) and nanosilica (NS) in the assessment based on digital image processing procedure. Theoretical and Applied Fracture Mechanics, 131, 104442.
[23]. Broch, E. (1983). Estimation of strength anisotropy using the point-load test. International Journal of Rock Mechanics and Mining Sciences, 20(4), 181–187.
[24]. Al-Harthi, A. A. (1998). Effect of planar structures on the anisotropy of Ranyah sandstone, Saudi Arabia. Engineering Geology, 50, 49–57.
[25]. Wang, G., Yang, D., Liu, S., et al. (2021). Experimental study on the anisotropic mechanical properties of oil shales under real-time high-temperature conditions. Rock Mechanics and Rock Engineering, 54, 6565–6583.
[26]. Castro, J., Miranda, M., Olson, M. H., & Justo, J. (2024). Direct tensile testing of Moleanos limestone. Proceedings of Eurock 2024, Alicante, Spain.
[27]. Zhang, Y., Zhang, Q.-Y., Zhou, X.-Y., & Xiang, W. (2021). Direct tensile test of red sandstone under different loading rates with the self-developed centering device. Geotechnical and Geological Engineering, 39, 709–718.
[28]. Rabat, A., Tomas, R., & Cano, M. (2023). Assessing water-induced changes in tensile behaviour of porous limestones by means of uniaxial direct pull test and indirect methods. Engineering Geology, 313, 106962.
[29]. Pérez-Rey, I., Muñoz-Ibañez, A., González-Fernández, M. A., Muñiz-Menéndez, M., Herbón Penabad, M., Estévez-Ventosa, X., Delgado, J., & Alejano, L. R. (2023). Size effects on the tensile strength and fracture toughness of granitic rock in different tests. Journal of Rock Mechanics and Geotechnical Engineering, 15, 2179–2192.
[30]. Chenevert, M. E., & Gatlin, C. (1965). Mechanical anisotropies of laminated sedimentary rocks. Society of Petroleum Engineers Journal, 5, 67–77.
[31]. Potyondy, D. O. (2017). Simulating perforation damage with a flat-jointed bonded-particle material. Proceedings of the Fifty First US Rock Mechanics/Geomechanics Symposium, San Francisco, California, USA.
[32]. Potyondy, D. O., & Cundall, P. A. (2004). A bonded-particle model for rock. International Journal of Rock Mechanics and Mining Sciences, 41, 1329–1364.
[33]. Abharian, S., Sarfarazi, V., Rasekh, H., & Behzadinasab, M. (2022). Effects of concrete/gypsum bedding layers and their inclination angles on the tensile failure mechanism: Experimental and numerical studies. Case Studies in Construction Materials, 17(1), 89–99.