Geomechanics and Engineering

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Experimental investigation of the mechanical behaviors of grouted crushed coal rocks under uniaxial compression

  • Jin, Yuhao (School of Mechanics and Civil Engineering, China University of Mining and Technology) ;
  • Han, Lijun (School of Mechanics and Civil Engineering, China University of Mining and Technology) ;
  • Meng, Qingbin (State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology) ;
  • Ma, Dan (School of Resources & Safety Engineering, Central South University) ;
  • Wen, Shengyong (School of Mechanics and Civil Engineering, China University of Mining and Technology) ;
  • Wang, Shuai (State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology)
  • Received : 2017.03.23
  • Accepted : 2018.06.15
  • Published : 2018.10.30
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Abstract

A detailed understanding of the mechanical behaviors for crushed coal rocks after grouting is a key for construction in the broken zones of mining engineering. In this research, experiments of grouting into the crushed coal rock using independently developed test equipment for solving the problem of sampling of crushed coal rocks have been carried out. The application of uniaxial compression was used to approximately simulate the ground stress in real engineering. In combination with the analysis of crack evolution and failure modes for the grouted specimens, the influences of different crushed degrees of coal rock (CDCR) and solidified grout strength (SGS) on the mechanical behavior of grouted specimens under uniaxial compression were investigated. The research demonstrated that first, the UCS of grouted specimens decreased with the decrease in the CDCR at constant SGS (except for the SGS of 12.3 MPa). However, the UCS of grouted specimens for constant CDCR increased when the SGS increased; optimum solidification strengths for grouts between 19.3 and 23.0 MPa were obtained. The elastic moduli of the grouted specimens with different CDCR generally increased with increasing SGS, and the peak axial strain showed a slightly nonlinear decrease with increasing SGS. The supporting effect of the skeleton structure produced by the solidified grouts was increasingly obvious with increasing CDCR and SGS. The possible evolution of internal cracks for the grouted specimens was classified into three stages: (1) cracks initiating along the interfaces between the coal blocks and solidified grouts; (2) cracks initiating and propagating in coal blocks; and (3) cracks continually propagating successively in the interfaces, the coal blocks, and the solidified grouts near the coal blocks. Finally, after the propagation and coalescence of internal cracks through the entire specimens, there were two main failure modes for the failed grouted specimens. These modes included the inclined shear failure occurring in the more crushed coal rock and the splitting failure occurring in the less crushed coal rock. Both modes were different from the single failure mode along the fissure for the fractured coal rock after grouting solidification. However, compared to the brittle failure of intact coal rock, grouting into the different crushed degree coal rocks resulted in ductile deformation after the peak strength for the grouted specimens was attained.

Keywords

References

  1. Dayakar, P., Raman, K.V. and Raju, K.V.B. (2012), "Study on permeation grouting using cement grout in sandy soil", IOSR J. Mech. Civ. Eng., 4(4), 5-10. https://doi.org/10.9790/1684-0440510
  2. El Mohtar, C.S. and Rugg, D.A. (2011), "New three-way split mold design and experimental procedure for testing soft, grouted soils", Geotech. Test. J., 34(6), 1-13.
  3. Funehag, J. and Fransson, A. (2006), "Sealing narrow fractures with a Newtonian fluid: Model prediction for grouting verified by field study", Tunn. Undergr. Sp. Technol., 21(5), 492-498. https://doi.org/10.1016/j.tust.2005.08.010
  4. Gopinathan, S. and Anand, K.B. (2017), "Properties of cement grout modified with ultra-fine slag", Front. Struct. Civ. Eng., 12(1), 1-9. https://doi.org/10.1007/s11709-017-0485-8
  5. Khayat, K.H., Yahia, A. and Sayed, M. (2008), "Effect of supplementary cementitious materials on rheological properties, bleeding, and strength of structural grout", ACI Mater. J., 105(6), 585-593.
  6. Ma, D., Cai, X., Zhou, Z.L. and Li, X.B. (2018), "Experimental investigation on hydraulic properties of granular sandstone and mudstone mixtures", Geofluids.
  7. Ma, D., Rezania, M., Yu, H.S. and Bai, H.B. (2017), "Variations of hydraulic properties of granular sandstones during water inrush: Effect of small particle migration", Eng. Geol., 217, 61-70.
  8. Ma, D., Zhou, Z.L., Wu, J.Y., Li, Q. and Bai, H.B. (2017), "Grain size distribution effect on the hydraulic properties of disintegrated coal mixtures", Energies, 10(5), 612. https://doi.org/10.3390/en10050612
  9. Mohammed, M.H., Pusch, R., Knutsson, S. and Gunnar, H. (2014), "Rheological properties of cement-based grouts determined by different techniques", Engineering, 6(5), 217-229. https://doi.org/10.4236/eng.2014.65026
  10. Mohammed, M. H., Pusch, R. and Knutsson, S. (2015), "Study of cement-grout penetration into fractures under static and oscillatory conditions", Tunn. Undergr. Sp. Technol., 45, 10-19.
  11. Mohtar, C.E., Yoon, J. and Elkhattab, M. (2015), "Experimental study on penetration of bentonite grout through granular soils", Can. Geotech. J., 52(11), 1850-1860. https://doi.org/10.1139/cgj-2014-0422
  12. Rahman, M., Hakansson, U. and Wiklund, J. (2015), "In-line rheological measurements of cement grouts: Effects of water/cement ratio and hydration", Tunn. Undergr. Sp. Technol., 45, 34-42.
  13. Saric, C.M., Khayat, K.H. and Tagnit, H.A. (2003), "Performance characteristics of cement grouts made with various combinations of high-range water reducer and cellulose-based viscosity modifier", Cement Concrete Res., 33(12), 1999-2008. https://doi.org/10.1016/S0008-8846(03)00214-X
  14. Sui, W.H., Liu, J.Y., Hu, W., Qi, J.F. and Zhan, K.Y. (2015), "Experimental investigation on sealing efficiency of chemical grouting in rock fracture with flowing water", Tunn. Undergr. Sp. Technol., 50(1), 239-249.
  15. Voottipruex, P. and Jamsawang, P. (2014), "Characteristics of expansive soils improved with cement and fly ash in Northern Thailand", Geomech. Eng., 6(5), 437-453. https://doi.org/10.12989/gae.2014.6.5.437
  16. Wang, Q., Wang, S., Sloan, S.W., Sheng, D.C. and Pakzad, R. (2016), "Experimental investigation of pressure grouting in sand", Soil. Found., 56(2), 161-173. https://doi.org/10.1016/j.sandf.2016.02.001
  17. Wang, S.Y., Chan, D.H., Lam, K.C. and Au, S.K.A. (2013), "A new laboratory apparatus for studying dynamic compaction grouting into granular soils", Soil. Found., 53(3), 462-468. https://doi.org/10.1016/j.sandf.2013.04.007
  18. Xue, X.H. (2015), "Study on relations between porosity and damage in fractured rock mass", Geomech. Eng., 9(1), 15-24. https://doi.org/10.12989/gae.2015.9.1.015
  19. Yang, Z.Q., Hou, K.P., Wei, L., Yong, C. and Yang, B.J. (2014), "Study of diffusion parameters of Newtonian fluid based on column-hemispherical penetration grouting", Rock Soil Mech., 35(S2), 47-53.
  20. Zheng, G., Zhang, X.S., Diao, Y. and Lei, H.Y. (2016), "Experimental study on the performance of compensation grouting in structured soil", Geomech. Eng., 10(3), 335-355. https://doi.org/10.12989/GAE.2016.10.3.335
  21. Zhou, J. W., Liu, Y., Du, C.L. and Wang, F.R. (2015), "Experimental study on crushing characteristic of coal and gangue under impact load", Int. J. Coal. Prepar. Utiliz., 36(5), 272-282.
  22. Zhou, Z.L., Cai, X., Ma, D., Cao, W.Z., Chen, L. and Zhou, J. (2018), "Effects of water content on fracture and mechanical behavior of sandstone with a low clay mineral content", Eng. Fract. Mech., 193, 47-65. https://doi.org/10.1016/j.engfracmech.2018.02.028

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