Advertisement

The compression and collapse behaviour of intact loess in suction-monitored triaxial apparatus

  • Dengfei Zhang
  • Jiading WangEmail author
  • Cunli Chen
  • Songhe Wang
Research Paper
  • 56 Downloads

Abstract

Loess is susceptible to large and sudden volume reduction induced by loading or wetting. The work in this paper focused on compression and collapse behaviour of the intact loess under isotropic stress condition. To this purpose, an improved technique was introduced for the unsaturated triaxial apparatus that was capable of precise injecting know the amounts of water into the specimen, while continuously monitoring the suction. Tests were performed under two separate hydro-mechanical paths: isotropic compression at various suctions and wetting in steps at various net isotropic stresses. Experimental measurements indicated that the compression behaviour of the intact loess was highly affected by the extent of the level of the suction. The wetting-induced collapse behaviour depended on both the extent of applied net isotropic stress and the hydro-mechanical path. The collapse potential reached a maximum when the specimen was wetted at the initial yield stress. No unique of yield curve was identified from loading and wetting paths in a suction–net mean stress plane. For the same plastic volumetric strain, the suction decrease yield curve identified from wetting path appeared under the loading–collapse yield curve identified from loading path. Interestingly, the uniqueness of the yield curve was identified from loading and wetting paths in a suction–mean effective stress plane. An elastoplastic model of the intact loess under isotropic stress condition incorporating soil water retention behaviour was proposed, using the mean effective stress as constitutive stress. This model is able to reproduce the volumetric behaviour of the intact loess along constant suction paths and wetting paths quite well, using a single-valued compressibility index.

Keywords

Collapse upon wetting Collapsible loess Compression deformation Elastoplastic model Yield 

List of symbols

σ3

Confining pressure

p

Net isotropic stress

p

Mean skeleton stress, or “mean effective stress”

ua

Pore air pressure

uw

Pore water pressure

s

Suction

\(s^{*}\)

Loss suction

e

Void ratio

w

Water content

Sr

Degree of saturation

\(S_{\text{r}}^{0}\)

Degree of saturation at zero suction

sc

Entry-air value

α, n, m

Parameters of the VG model

sc0, β

Parameters for identifying the change of sc with net isotropic stress p

\(p_{\text{y}}^{*}\)

Yield stress at unsaturated state

py0

Yield stress at saturated state

\(p_{\text{y}}^{{{\prime }*}}\)

Effective yield stress at unsaturated state

\(p_{\text{ref}}^{{\prime }}\)

Reference mean effective stress

sy

Collapse suction

εv

Total volumetric strain

\(\varepsilon_{\text{v}}^{\text{e}}\)

Elastic volumetric strain

\(\varepsilon_{\text{v}}^{\text{p}}\)

Plastic volumetric strain

κvs

Slope of the e–ln p curve before yielding

λvs

Slope of the e–ln p curve after yielding

\(\kappa_{\text{vs}}^{{\prime }}\)

Slope of the e–ln p′ curve before yielding

\(\lambda_{\text{vs}}^{{\prime }}\)

Slope of the e–ln p′ curve after yielding

λv0

Value of λvs at zero suction

a, b

Parameters for identifying the change of λvs with suction s

a1, b1

Parameter for identifying the change of \(\lambda_{\text{vs}}^{{\prime }}\) with suction s

N(s)

Intercept of the unsaturated isotropic normal compression line in the e–ln \(p^{{\prime }} /p_{\text{ref}}^{{\prime }}\) plane

N(0)

Intercept of the saturated isotropic normal compression line in the e–ln \(p^{{\prime }} /p_{\text{ref}}^{{\prime }}\) plane

λvp

Slope of the e–ln \(s^{*}\) curve after yielding

C1, C2

Parameters for identifying the change of λvp with net isotropic stress p

Notes

Acknowledgements

The National Key Research and Development Plan (2018YFC1504703), National Natural Science Foundation of China (Grant Nos. 41630639 and 51778528), the Certificate of China Postdoctoral Science Foundation Grant (2018M633559), the Key Laboratory Programme of Department of Education of Shaanxi Province of China (Grant No. 14JS063) supported the present study. The authors also want to express their deep thanks to the anonymous reviewers for their constructive comments.

References

  1. 1.
    Alonso EE, Gens A, Josa A (1990) Constitutive model for partially saturated soils. Geotechnique 40(3):405–430Google Scholar
  2. 2.
    Chen CL, Gao P, Hu ZQ (2006) Moistening deformation characteristic of loess and its relation to structure. Chin J Rock Mech Eng 25(7):1352–1360Google Scholar
  3. 3.
    Cui YJ, Delage P (1996) Yielding and plastic behaviour of an unsaturated compacted silt. Geotechnique 46(2):291–311Google Scholar
  4. 4.
    Futai MM, Almeida MSS, Soares MM (1998) Evaluation of collapse by means of laboratory tests (in portuguese). In: XI Brazilian conference on soil mechanics and geotechnical engineering, Brasília, pp 1023–1030Google Scholar
  5. 5.
    Futai MM, Conciani W, Silva Fiho FC (2002) Experimental and theoretical evaluation of plate load test in collapsible soil. In: Proceedings of third international conference on unsaturated soils, vol 2, Recife, Brazil. BalkemaGoogle Scholar
  6. 6.
    Gao GR (1996) The distribution and geotechnical properties of loess soils, lateritic soils and clayey soils in China. Eng Geol 42(1):95–104MathSciNetGoogle Scholar
  7. 7.
    Garakani AA, Haeri SM, Khosravi A, Habibagahi G (2015) Hydro-mechanical behavior of undisturbed collapsible loessial soils under different stress state conditions. Eng Geol 195(10):28–41Google Scholar
  8. 8.
    Gallipoli D (2012) A hysteretic soil-water retention model accounting for cyclic variations of suction and void ratio. Geotechnique 62(7):605–616Google Scholar
  9. 9.
    Guo MX, Zhang SH, Xing YC (2000) Collapse deformation and pore pressure characteristics of unsaturated intact loess. Chin J Rock Mech Eng 19(6):785–788Google Scholar
  10. 10.
    Haeri SM, Garakani AA, Khosravi A, Meehan CL (2014) Assessing the hydromechanical behaviour of collapsible soils using a modified triaxial test device. Geotech Test J 37(2):190–204Google Scholar
  11. 11.
    Haeri SM, Khosravi A, Garakani AA, Ghazizadeh S (2016) Effect of soil structure and disturbance on hydromechanical behavior of collapsible loessial soils. Int J Geomech 17(1):04016021Google Scholar
  12. 12.
    Houlsby GT (1997) The work input to an unsaturated granular material. Geotechnique 47(1):193–196Google Scholar
  13. 13.
    Jiang MJ, Hu HJ, Liu F (2012) Summary of collapsible behaviour of artificially structured loess in oedometer and triaxial wetting tests. Can Geotech J 49(10):1147–1157Google Scholar
  14. 14.
    Jotisankasa A, Coop M, Ridley A (2009) The mechanical behaviour of an unsaturated compacted salty clay. Geotechnique 59(5):415–428Google Scholar
  15. 15.
    Jotisankasa A, Ridley A, Coop M (2007) Collapse behavior of a compacted salty clay in the suction-monitored odometer apparatus. J Geotech Geoenviron Eng ASCE 133(7):867–877Google Scholar
  16. 16.
    Kohgo Y, Nakano M, Miyazaki T (1993) Theoretical aspects of constitutive modelling for unsaturated soils. Soils Found 33(4):49–63Google Scholar
  17. 17.
    Li JG, Chen ZH, Huang XF (2010) CT-triaxial test for collapsibility of undisturbed Q3 loess. Rock Mech Eng 29(6):1288–1296Google Scholar
  18. 18.
    Liu BJ, Xie DY, Guo ZY (2004) A practical method for moistening deformation of loess foundation. Rock Soil Mech 25(2):270–274Google Scholar
  19. 19.
    Liu DS (1985) Loess and the environment. China Ocean Press, BeijingGoogle Scholar
  20. 20.
    Liu DS, Zhang ZH (1962) Loess of China. Acta Geol Sin 42(1):1–14Google Scholar
  21. 21.
    Liu ZD (1996) Loess mechanics and engineering. Science and Technology Press of Shaanxi, Xi’anGoogle Scholar
  22. 22.
    Lin ZG, Shu TK (1958) Preliminary study of collapsibility of loess in Northwest China. Hydrogeol Eng Geol 2(4):1–7Google Scholar
  23. 23.
    Luo XF, Wang YY, Cui GH (2014) Study on immersion test and settlement deformation on loess foundation of high-speed railway. Site Invest Sci Technol 2:1–4Google Scholar
  24. 24.
    Maatouk A, Leroueil S, Rochelle P (1995) Yielding and critical state of a collapsible unsaturated silty soil. Geotechnique 45(3):465–477Google Scholar
  25. 25.
    Munoz-Castelblanco J, Delage P, Pereira JM, Cui YJ (2011) Some aspects of the compression and collapse behaviour of an unsaturated natural loess. Geotech Lett 1:17–22Google Scholar
  26. 26.
    Nuth M, Laloui L (2008) Effective stress concept in unsaturated soils: clarification and validation of a unified framework. Int J Numer Anal Methods Geomech 32(7):771–801zbMATHGoogle Scholar
  27. 27.
    Pereira JHF, Fredlund DG, Cardao Neto MP et al (2005) Hydraulic behavior of collapsible compacted gneiss soil. J Geotech Geoenviron Eng ASCE 131(10):1264–1273Google Scholar
  28. 28.
    Pereira HFJ, Fredlund DG (2000) Volume change behavior of collapsible compacted gneiss soil. J Geotech Geoenviron Eng ASCE 126(10):907–916Google Scholar
  29. 29.
    Rojas E, Pérez-Rea ML, López-Lara T et al (2015) Use of effective stresses to model the collapse upon wetting in unsaturated soils. J Geotech Geoenviron Eng ASCE 141(5):04015007–04015013Google Scholar
  30. 30.
    Sheng DC, Fredlund DG, Gens A (2008) A new modeling approach for unsaturated soils using independent stress variables. Can Geotech J 45(4):511–534Google Scholar
  31. 31.
    Sheng DC, Sloan SW, Gens A (2004) A constitutive model for unsaturated soils: thermomechanical and computational aspects. Comput Mech 33(6):453–465zbMATHGoogle Scholar
  32. 32.
    Sun DA, Matsuoka H, Xu YF (2004) Collapse behavior of compacted clays by suction-controlled triaxial tests. Geotech Test J ASTM 27(4):362–370Google Scholar
  33. 33.
    Sun DA, Matsuoka H, Yao YP et al (2000) A three-dimensional elastoplastic model for unsaturated compacted soil with hydraulic hysteresis. Soils Found 47(2):253–264Google Scholar
  34. 34.
    Sun P, Peng JB, Chen LW, Yin YP, Wu SR (2009) Weak tensile characteristics of loess in China—an important reason for ground fissures. Eng Geol 108(1):153–159Google Scholar
  35. 35.
    Sun DA, Sheng DC, Xu YF (2007) Collapse behaviour of unsaturated compacted soil with different initial densities. Can Geotech J 44(6):673–686Google Scholar
  36. 36.
    Tan YZ, Kong LW, Guo AG et al (2011) Experimental study on wetting deformation of compacted laterite. Chin J Geotech Eng 33(3):483–489Google Scholar
  37. 37.
    van Genuchten MT (1980) A closed form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci Soc Am J 44:892–898Google Scholar
  38. 38.
    Wang JD, Li P, Ma Y, Vanapalli SK (2019) Evolution of pore-size distribution of intact loess and remolded loess due to consolidation. J Soils Sediments 19(3):1226–1238Google Scholar
  39. 39.
    Wheeler SJ, Sivakumar V (1995) An elasto-plastic critical state framework for unsaturated soil. Geotechnique 45(1):35–53Google Scholar
  40. 40.
    Wheeler SJ, Sharma RS, Buisson MSR (2003) Coupling of hydraulic hysteresis and stress–strain behaviour in unsaturated soils. Geotechnique 53(1):41–54Google Scholar
  41. 41.
    Xing YC, Li JS, Li Z (2007) Deformation characteristics of collapsible loess and expansive soil under the condition of wetted in stages. J Hydraul Eng 38(5):546–551Google Scholar
  42. 42.
    Xu L, Dai FC, Tham LG, Tu XB, Min H, Zhou YF et al (2011) Field testing of irrigation effects on the stability of a cliff edge in loess, North-west China. Eng Geol 120(1):10–17Google Scholar
  43. 43.
    Yao YP, Niu L, Han LM et al (2011) Experimental study of behaviour for overconsolidated unsaturated soils. Rock Soil Mech 32(6):1601–1606Google Scholar
  44. 44.
    Zhang DF, Chen CL, Yang J et al (2016) Deformation and water retention behaviour of collapse loess during wetting under the condition of lateral confinement. Chin J Rock Mech Eng 35(3):604–612Google Scholar
  45. 45.
    Zhang DF (2017) Behaviours of hydro-mechanical and laws of water and gas permeability during wetting for intact loess. Xi’an University of Technology, Xi’anGoogle Scholar
  46. 46.
    Zhang LS (2001) Discussions on test methods of collapsible loess. Rock Soil Mech 22(1):207–210Google Scholar
  47. 47.
    Zhang MH, Xie YL, Liu BJ (2005) Characteristics of collapsibility coefficient curves of loess during moistening and demoistening process. Rock Soil Mech 26(9):1363–1368Google Scholar
  48. 48.
    Zhang SM, Zheng JG (1990) The effect of the sequence of load application and water on mechanics characteristics of collapsible loess. Site Invest Sci Technol 3:10–14Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Dengfei Zhang
    • 1
  • Jiading Wang
    • 1
    Email author
  • Cunli Chen
    • 2
  • Songhe Wang
    • 2
  1. 1.State Key Laboratory of Continental Dynamics, Department of GeologyNorthwest UniversityXi’anChina
  2. 2.Shaanxi Provincial Key Laboratory of Loess Mechanics and EngineeringXi’an University of TechnologyXi’anChina

Personalised recommendations