DOI QR코드

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Fiber orientation distribution of reinforced cemented Toyoura sand

  • Safdar, Muhammad (Earthquake Engineering Center, Department of Civil Engineering, University of Engineering and Technology Peshawar) ;
  • Newson, Tim (Department of Civil and Environmental Engineering, Western University) ;
  • Waseem, Muhammad (Department of Civil Engineering, University of Engineering and Technology Peshawar)
  • 투고 : 2020.11.25
  • 심사 : 2022.06.07
  • 발행 : 2022.07.10

초록

In this study, the fiber orientation distribution (FOD) is investigated using both micro-CT (computerized tomography) and image analysis of physically cut specimens prepared from Polyvinyl Alcohol (PVA) fiber reinforced cemented Toyoura sand. The micro-CT images of the fiber reinforced cemented sand specimens were visualized in horizontal and vertical sections. Scans were obtained using a frame rate of two frames and an exposure time of 500 milliseconds. The number of images was set to optimize and typically resulted in approximately 3000 images. Then, the angles of the fibers for horizontal sections and in vertical section were calculated using the VGStudio MAX software. The number of fibers intersecting horizontal and vertical sections are counted using these images. A similar approach was used for physically cut specimens. The variation of results of fiber orientation between micro-CT scans and visual count were approximately 4-8%. The micro-CT scans were able to precisely investigate the fiber orientation distribution of fibers in these samples. The results show that 85-90% of the PVA fibers are oriented between ±30° of horizontal, and approximately 95% of fibers have an orientation that lies within ±45° of the horizontal plane. Finally, a comparison of experimental results with the generalized fiber orientation distribution function 𝜌(θ) is presented for isotropic and anisotropic distribution in fiber reinforced cemented Toyoura sand specimens. Experimentally, it can be seen that the average ratio of the number of fibers intersecting the finite area on a vertical plane to number of fibers intersecting the finite area on a horizontal plane (NVtot/NHtot) cut through a sample varies from 2.08 to 2.12 (an average ratio of 2.10 is obtained in this study). Based up on the analytical predictions, it can be seen that the average NVtot/NHtot ratio varies from 2.13 to 2.17 for varying n values (an average ratio of 2.15).

키워드

과제정보

The research project was financially supported by the Western Graduate Research Scholarship at the Department of Civil and Environmental Engineering, Western University, London, Ontario, Canada. The authors would also like to acknowledge the Department of Sustainable Archaeology, Western University for providing Micro-CT Scan facility.

참고문헌

  1. Armaghani, D.J., Mirzaei, F., Toghroli, A. and Shariati A. (2020), "Indirect measure of shear strength parameters of fiber-reinforced sandy soil using laboratory tests and intelligent systems", Geomech. Eng., 22(5), 397-414. https://doi.org/10.12989/gae.2020.22.5.397
  2. Bahrami, M. and Marandi, S.M. (2020), "Effect of strain level on strength evaluation of date palm fiber-reinforced sand", Geomech. Eng., 21(4), 327-336. https://doi.org/10.12989/gae.2020.21.4.327
  3. Choi, S.G., Wang, K. and Chu, J. (2016), "Properties of biocemented, fiber reinforced sand", Constr. Build. Mater., 120(1), 623-629, https://doi.org/10.1016/j.conbuildmat.2016.05.124.
  4. Choi, S.G., Hoang, T., Alleman, E.J. and Chu, J. (2019), "Splitting tensile strength of fiber-reinforced and biocemented sand", J. Mater. Civil Eng., 31(9). https://doi.org/10.1061/(ASCE)MT.1943-5533.0002841.
  5. Diambra, A. (2010), "Fiber reinforced sands: experiments and modelling. PhD Dissertation, University of Bristol, UK.
  6. Diambra, A., Russell A.R., Ibraim E. and Wood D.M. (2007), "Determination of fiber orientation distribution in reinforced sand", Geotechnique, 57(7), 623-628. https://doi.org/10.1680/geot.2007.57.7.623.
  7. Gao, Z. and Zhao, J. (2012), "Constitutive modeling of artificially cemented sand by considering fabric anisotropy", Comput. Geotech., 41, 57-69. https://doi.org/10.1016/j.compgeo.2011.10.007.
  8. Ghadr, S. and Bahadori, H. (2017), "Anisotropic behavior of fiber-reinforced sands", J. Mater. Civil Eng., 31(11). https://doi.org/10.1061/(ASCE)MT.1943-5533.0002917.
  9. Ibraim, E., Diambra, A., Russell, A.R. and Wood, D.M. (2012), "Assessment of laboratory sample preparation for fiber reinforced sands", Geotext. Geomembranes, 34, 69-79. https://doi.org/10.1016/j.geotexmem.2012.03.002.
  10. Kanchi, G.M., Neeraja, V.S. and Babu, G.L.S. (2015), "Effect of anisotropy of fibers on the stress-strain response of fiber-reinforced soil", Int. J. Geomech., 15(1). https://doi.org/10.1061/(ASCE)GM.19435622.0000392.
  11. Klages, A.M. (2013), "A micro-CT analysis of the hominoid subnasal anatomy", Master Thesis, Western University, London, Ontario, Canada.
  12. Ladd, R.S. (1978), "Preparing test specimens using undercompaction", Geotech. Test. J., ASTM, 1(1), 16-23. https://doi.org/10.1520/GTJ10364J.
  13. Li, M., Li, L., Ogbonnaya, U., Wen, K., Tian, A. and Amini, F. (2016), "Influence of fiber addition on mechanical properties of MICP-treated sand", J. Mater. Civil Eng., 28(4). https://doi.org/10.1061/(ASCE)MT.1943-5533.0001442.
  14. Michalowski, R.L. (1997), "Limit stress for granular composites reinforced with continuous filaments", J. Eng. Mech., 123(8), 852-859. https://doi.org/10.1061/(ASCE)07339399(1997)123:8(852).
  15. Michalowski, R.L. (2008), "Limit analysis with anisotropic fiber-reinforecd soil", Ge'otechnique, 58(6), 89-501. https://doi.org/10.1680/geot.2008.58.6.489.
  16. Michalowski, R.L. and Cermak, J. (2002), "Strength anisotropy of fiber-reinforced sand", Comput. Geotechnics, 29(4) ,279-299. https://doi.org/10.1016/S0266-352X(01)00032-5.
  17. Safdar, M. (2018), "Monotonic Stress-Strain Behaviour of Fibre Reinforced Cemented Toyoura Sand", Ph.D. Dissertation, Western University, London, Ontario, Canada. https://ir.lib.uwo.ca/etd/5622.
  18. Safdar, M., Newson, T., Schmidt C., et al. (2020), "Effect of fibre and cement additives on the small-strain stiffness behaviour of Toyoura sand", Sustainability, 12, 10468. https://doi.org/10.3390/su122410468.
  19. Salah-ud-din, M. (2012), "Behaviour of fiber reinforced cemented sand at high pressures", Ph.D. Dissertation, University of Nottingham, UK. http://eprints.nottingham.ac.uk/12545/1/Thesis_Salah.pdf.
  20. Schmidt, C.J.R. (2015), "Static and Dynamic Response of Silty Toyoura Sand with PVA Fiber and Cement Additives", Master Thesis, Western University, London, Ontario, Canada.
  21. Shukla, S.K. (2017), "Basic Description of Fiber-Reinforced Soil, In: Fundamentals of Fiber-Reinforced Soil Engineering Developments in Geotechnical Engineering", Springer, Singapore. https://doi.org/10.1007/978-981-10-3063-5_2.
  22. Sonmezer, Y.B. (2019), "Investigation of the liquefaction potential of fiber-reinforced sand", Geomech. Eng., 18(5), 503-513. https://doi.org/10.12989/gae.2019.18.5.503.
  23. Soriano, I., Ibraim, E. and Ando, E., et al. (2017), "3D fibre architecture of fibre-reinforced sand", Granular Matter, 19(75). https://doi.org/10.1007/s10035-017-0760-3.
  24. Wood, D.M., Diambra, A. and Ibraim, E. (2016), "Fibres and soils: A route towards modelling of root-soil systems", Soils Found., 56(5), 765-778. https://doi.org/10.1016/j.sandf.2016.08.003.