Xiang Huang1,2, Hong-bin Chen1, Xue-Jun Chen This email address is being protected from spambots. You need JavaScript enabled to view it.1,2, De-xian Liang2, Han-ying Bai2, Yu Song1,2

1Guilin University of Technology, Guilin 541004,P.R. China
2Guangxi Key Laboratory of Geotechnical Engineering,Guilin 541004, P.R. China


 

Received: December 12, 2018
Accepted: February 28, 2020
Publication Date: June 1, 2020

Download Citation: ||https://doi.org/10.6180/jase.202006_23(2).0020  

ABSTRACT


To develop a damage index to describe the stress-strain relationship of red clay in Guilin, the undrained triaxial tests of intact red clay under various confining pressures were conducted. Firstly, the initial deformation modulus was analyzed based on the hyperbolic strain-stress relationship and deformation modulus-confining pressure relationship. The change law of secant modulus and strain threshold value were determined based on the relationship between the axial strain and secant modulus. The variable D related with the initial elastic modulus and secant modulus are used as damage index, which increased with the increase of the principal stress difference, showing a linear relationship. The damage index was correlated with the axial strain exponentially, indicating that the damage of red clay was irreversible. The proposed variable D was used in the nonlinear damages mechanics model to compare with experimental data, and the constitutive model based on the damage index D reflected the experiment results and fitted the stress-strain curves of the red clay.


Keywords: red clay; triaxial test; damage index; evolution law of damages


REFERENCES


 

  1. [1] Shen, Z. J., “An elasto-plastic damage model for cemented clays,” Chinese Journal of Geotechnical Engineering, Vol. 15, No. 03, pp. 21-28 (2007).
  2. [2] Shen, Z.J., “A nonlinear damage model for structured clay,” Hydro-Science and Engineering, Vol. 03, pp. 247-555 (1993). doi: 0.16198/j.cnki.1009-640x.2002.04.002
  3. [3] He, K.S., Shen, Z.J., “Elasto-viscoplastic damage model for structural clays,” Hydro-Science and Engineering, Vol. 04, pp. 7-13 (2002).
  4. [4] Cheng, Z., She, Z.J., and Chen T.L., “A bounding surface masonry model for structured clays,” Rock and Soil Mechanics, Vol. 24, No. 3, pp. 317-320 (2003). doi: 10.13243/j.cnki.slxb.2004.01.016
  5. [5] Wang, L.Z., Zhao, Z.Y, and Li, L.L., “Non-linear elastic model considering soil structural damage,” Shuili Xuebao, Vol. 1, pp. 83-89 (2004).
  6. [6] Zhang, B.Y., Soil constitutive model based on structured soil. Master thesis, Dalian University of Technology, Dalian (2006).
  7. [7] Xia, W.M., The elasto-plastic damage constitutive model of loess and its engineering application. Ph.D. Dissertation, Xi’an University of Technology, Xi’an (2005).
  8. [8] Wang, Y., Research on the viscoelastic-viscoplastic-damage model of structural soft soil. Ph.D. Dissertation, Wuhan university of technology, Wuhan (2006).
  9. [9] Jiang, C.L., Study on structure damage and evolution of loess. Ph.D. Dissertation, Northweat A&F University, Xianyang (2008).
  10. [10] Chen, M. S., Wang, S.J., Mao, X. and et al, “Fissure morphology and mechanical characterization for structure-damaged expansive soil under triaxial compression tests,” Chinese Journal of Geotechnical Engineering, Vol. 38, No. S2, pp. 73-78.
  11. [11] Xiong, C.F., Cao, Y., “Analysis on the influencing factor of structure damage of marine soft clay,” Journal of Wuhan university of technology, Vol. 35, No. 11, pp. 90-93 (2013).
  12. [12] Zhang, T.W., Xu, H.B., Deng, Y.F. “A study of the correlation between the damage index and disturbance degree of structural soft clay,” Rock and Soil Mechanics, Vol. 36, No. 04, pp. 958-964 (2015). doi:10.16285/j.rsm.2015.04.007
  13. [13] Chen, X.J., Huang, X, Shao, H.B and Qi, Y.L. “Study on the shear strength characteristics of the remolded laterite soil in Guilin,” Unsaturated Soil Mechanics-from theory to practice: Proceedings of 6th Asia Pacific conference on unsaturated soil, Guilin, China, October 23-26,2 015.
  14. [14] Chen, X.J., Li, J.C., Song Y., Bai H.Y. “Effect of nano graphite powder on mechanical properties of red clay” Journal of Engineering Geology, Vol.26, No. 01, pp.97-102 (2018). doi: 10.13544/j.cnki.jeg.2018.01.011
  15. [15] Chen, X.J., Hu, S.W., Huang, Y.Y., Bai, H.Y., “Experimental study on strength characteristic of red clay under influence of nano-CaCO3Journal of Engineering Geology, Vol.5, pp. 1293-1298. (2017). doi: 10.13544/j.cnki.jeg.2017.05.015.
  16. [16] Kondner, R.L., “Hyperbolic stress-strain response: cohesive soils,” Journal of the Soil Mechanics and Foundations Division, Vol. 89, No. SM1, pp. ll5-143 (1963). doi: 10.1016/0022-4898(64)90153-3 
  17. [17] Zhang, Y., Kong, L.W., Meng Q.S. and et al., “Normalized stress-strain behavior of Wuhan soft clay” Rock and Soil Mechanics, Vol. 27, No.9, pp. 1509-1513 (2006). doi: 10.16285/j.rsm.2006.09.015
  18. [18] Zhao, X.H., Sun H., Luo G.W., Damage soil Mechanics. Tongji University Press, Shanghai, pp 19-21 (2002).
  19. [19] Lin, B., Research on rheological model of loess in considering of damage effect. Ph.D. Dissertation, Chang’an University (2005).