A Compression Model for Unsaturated Collapsible soils

Document Type : Original Research

Authors
A. Farsijani 1
A. Ouria 2
1 Ph. D. Candidate of Department of Civil Engineering, University of Mohaghegh Ardabili, Iran
2 Associate Professor Department of Civil Engineering, University of Mohaghegh Ardabili , Iran
DOI: 10.22034/22.2.9
Abstract
Abstract

Since most of the soils in their natural state are unsaturated, therefore understanding and description of the compression and failure behavior of unsaturated soils are essential. The compression and failure behavior of unsaturated soils are affected by the interaction of the solid, liquid, and gas phases of the soil. Most of unsaturated soils exhibit a sudden change in their volume due to saturation that is called collapse phenomenon. The compression and collapse behavior of collapsible soils are so complex that can not be explained in the total or net stress spaces. Wetting induced collapse of the collapsible soil has a discontinuous response in net stress space and needs to be described using the matric suction. Calculations of the effective stress using the matric suction shows that the wetting induced collapse response of unsaturated soils is a continuous but a highly non-linear behavior. On the other hand, the compression characteristics of dry and saturated soils are different and change as the moisture content or the degree of the saturation of the soil change. In this research the compression and the wetting induced collapse behavior of unsaturated CL-ML soil have been investigated in the laboratory. Laboratory tests have been conducted by oedometer test device. Compression and wetting induced collapse behavior of unsaturated soil in dry state before collapse, during saturation and collapse state, and fully saturated after collapse state were studied. Pressure plate device was employed to obtain the soil water characteristic curve of the soil. Based on the laboratory results a compression and collapse model has been proposed to capture the compression and collapse behavior of the soil before, during and after wetting induced collapse. Using the soil water characteristic curve, the compression and collapse response of the soil was transferred to effective stress space. The binary-medium model was employed to describe the compression and the collapse behavior of the unsaturated soil based on its responses in two dry and fully saturated states as two reference states. Based on the binary-medium model, soil mass was considered as binary medium including two states of 0 and 1. The state of the soil in dry condition was considered as binary 0 and its state in fully saturated state was considered as binary 1. The state of the soil at any particular state between these two states was interpolated using a state function. An exponential form state function in terms of matric suction and the effective stress was introduced to relate the volume change of the unsaturated soil during the collapse state to its compression behavior in two dry and fully saturated states The state function was derived based on the laboratory experiments. The compression behavior of the soil in dry state was. Using the proposed model, the compression and collapse behavior of unsaturated soil in dry state, collapse state, and saturated state could be described in a single generalized model. The proposed model was verified by the laboratory tests conducted in this study and the available published in the literature. Verifications illustrated the ability of the proposed model in capturing the compression and collapse behavior of unsaturated collapsible soils.

Keywords

Subjects

1- A.R. Bagherieh, A. FarsijanI, (2016). ”Consolidation Behavior of collapsible clay soils in saturated and unsaturated conditions” , Sharif Civil Engineering Journal, pp 43-54(in persia)

2- Sheng, D. (2011). Review of fundamental principles in modeling unsaturated soil behavior", Journal of Computers and Geotechnics, 38(6), pp. 757-776.

3- Zheng, Z., Li, X., Wang, L., Li, L., Shi, J., & Bi, M. (2021). A new approach to evaluation of loess collapsibility based on quantitative analyses of colloid-clay coating with statistical methods. Engineering Geology, 288, 106167. https://doi.org/https://doi.org/10.1016/j.enggeo.2021.106167

4- Wang, J., Zhang, D., Chen, C., & Wang, S. (2020). Measurement and modelling of stress-dependent water permeability of collapsible loess in China. Engineering Geology, 266, 105393. https://doi.org/https://doi.org/10.1016/j.enggeo.2019.105393

5- Bagherien. A. R, Farsijani. A, Farpour. R, (2017). Comparison of stress variables performance in predicting the shear strength of unsaturated soils. Modares Civil Engineering Journal. (17) , 13-27.

6- Bagherien. A. R, Farpour. R, Farsijani. A, (2017). The collapse and creep behaviour of kaolin with double porosity structure. Modares Civil Engineering Journal. (16), 11-20.

7- Bagherien. A. R, Farsijani. A, The effect of moisture content on the shear strength parameters of plastic fine soils, . Modares Civil Engineering Journal.(3), 31-41.(in Persia)

8- Bagherieh, A. R., Khalili, N., Habibagahi, G., & Ghahramani, A. (2009). Drying response and effective stress in a double porosity aggregated soil. Engineering Geology. https://doi.org/10.1109/TNET.2015.2504603

9- Y., Pasha. A., Arman, Khoshghalb., & Nasser, K. (2017). Hysteretic Model for the Evolution of Water Retention Curve with Void Ratio. Journal of Engineering Mechanics, 143(7), 4017030. https://doi.org/10.1061/(ASCE)EM.19437889.0001238

10- Pasha, A., Khoshghalb, A., & Khalili, N. (2020). Evolution of isochoric water retention curve with void ratio. Computers and Geotechnics, 122, 103536. https://doi.org/https://doi.org/10.1016/j.compgeo.2020.103536

11- Zhou, A., Fan, Y., Cheng, J. W., & Zhang, J. (2019). A Fractal Model to Interpret Porosity-Dependent Hydraulic Properties for Unsaturated Soils. Advances in Civil Engineering, 2019, 1–13. https://doi.org/10.1155/2019/3965803

12- Ashour, M., Abbas, A., Altahrany, A., & Alaaeldin, A. (2020). Modelling the behavior of inundated collapsible soils. Engineering Reports, e12156. doi:10.1002/eng2.12156

13- Fredlund, D. G., & Gan, J. K.-M. (1995). The Collapse Mechanism of a Soil Subjected to One-Dimensional Loading and Wetting. Genesis and Properties of Collapsible Soils, 173–205. doi:10.1007/978-94-011-0097-7_9

14- AR Bagherieh, M Baharvand, M Meidani, A(2019) Mahboobi -Prediction of wetting-induced swelling using effective stress in an unsaturated kaolin Iranian Journal of Science and Technology

15- Sadeghabadi, A., Noorzad, A. & Zad, A. An Extension to Barcelona Basic Model Predicting the Behavior of Unsaturated Soils. Transp. Infrastruct. Geotech. (2021). https://doi.org/10.1007/s40515-021-00159-6

16- Garakani, A. A., Haeri, S. M., Khosravi, A., & Habibagahi, G. (2015). Hydro-mechanical behavior of undisturbed collapsible loessial soils under different stress state conditions. Engineering Geology, 195, 28–41. https://doi.org/https://doi.org/10.1016/j.enggeo.2015.05.026

17- Maleki, M., & Bayat, M. (2012). Experimental evaluation of mechanical behavior of unsaturated silty sand under constant water content condition. Engineering Geology, 141–142, 45–56. https://doi.org/https://doi.org/10.1016/j.enggeo.2012.04.014

18- Ghasemzadeh, H., & Akbari, F. (2019). Determining the bearing capacity factor due to nonlinear matric suction distribution in the soil. Canadian Journal of Soil Science, 99(4), 434–446. https://doi.org/10.1139/cjss-2019-0071

19- Fernando A. M. Marinho and Orlando M. Oliveira. (2005), The Filter Paper Method Revisited, Geotechnical Testing Journal, Vol. 29, No. 3,Paper ID GTJ14125

20- Bishop A. W(1959), "The principle of effective stress", Teknisk Ukeblad 106, pp 859-863.

21- Khalili, N., Khabaz, M. H., (1998)"A unique relationship for χ for the determination of the shera strength of unsaturated soils"; Journal of Geotechnique 48, No. 5, pp. 681-687.

22- Yan FR, W Fan, TY He, (2013) “Study on Binary-Medium Model of fissured loess”, Applied Mechanics and Materials, , (256- 59), 240-244.

23- Ouria. A, Ranjbarnia. M, vaezipour. D,(2018) A Failure Criterion for Weak Cemented Soils. Journal of Civil and Environmental Engineering 48 (92), 13-21

24- Sun, D., Sheng, D., Xu, Y., (2007). Collapse behaviour of unsaturated compacted soil with different initial densities. Can. Geotech. J. 44, 673–686. https://doi.org/10.1139/T07-023

25- Brink, G., and Heymann, G. (2014). “Soil collapse from an effective stress perspective.” Journal of theSouth African Institution of Civil Engineering, 56(3), 30–33.

26- Albadri, W. M., Jamaludin, M., and Alhani. I.,(2020). A new practical modification to the pressure plate extractor for measuring the wetting protion of SWCC. Austalian Geomechanics Journal. Vol 55. Number 2

27- Leong, E., Tripathy, S., & Rahardjo, H. (2004). A Modified Pressure Plate Apparatus. Geotechnical Testing Journal, 27, 322–331. https://doi.org/10.1520/GTJ11053

28- R., H. L., P., T., & J., P. A. (2021). A Modified Pressure Plate Device for SWCC Testing Under Anisotropic Stress States. In Unsaturated Soils 2006 (pp. 1753–1763). https://doi.org/doi:10.1061/40802(189)147

29- Khalili, N., Geiser, F., and Blight, G. E. (2004). “Effective stress in unsaturated soils: Review with new 414 evidence.” International Journal of Geomechanics, 4(2), 115–126.

30- Sun, D.A., Matsuoka, H., Xu, Y.F., 2004. Collapse behavior of compacted clays in suction-controlled triaxial tests. Geotech. Test. J. 27, 362–370. https://doi.org/10.1520/gtj11418

31- Pereira J.F.H., Fredlund D.G., 2000. Volume Change Behavior of Collapsible Compacted Gneiss Soil. J. Geotech. Geoenvironmental Eng. 126, 907–916. https://doi.org/10.1061/(ASCE)1090-0241(2000)126:10(907)

32- Desai, C.S., 2000a. Mechanics of Materials and Interfaces: The Disturbed State Concept, CRC. Boca Raton, FL.

33- Ouria, A., 2017. Disturbed state concept-based constitutive model for structured soils. International Journal of Geomechanics 17(7):04017008, https://doi.org/10.1061/(ASCE)GM.1943-5622.0000883

34- Ouria, A., Behboodi, T., 2017. Compressibility of Cement Treated Soft Soils. Journal of Civil and Environmental Engineering 47 (86), 1-9.

35- Ouria, A., Desai, C.S., Toufigh, V., 2015. Disturbed state concept-based solution for consolidation of plastic clays under cyclic loading. International Journal of Geomechanics 15(1):04014039, DOI: https://doi.org/10.1061/(ASCE)GM.1943-5622.0000336

36- Mirzaii, A., Yasrobi, S. S., & Hefzi, E. (2020). Critical state behaviour of an unsaturated clayey sand along constant water content direct shear and triaxial loading conditions. International Journal of Geotechnical Engineering, 14(3), 286–294. https://doi.org/10.1080/19386362.2018.1438151

37- Sadeghzadegan, R., Naeini, S. A., & Mirzaii, A. (2020). Effect of clay content on the small and mid to large strain shear modulus of an unsaturated sand. European Journal of Environmental and Civil Engineering, 24(5), 631–649. https://doi.org/10.1080/19648189.2017.1415169
Modares Civil Engineering journal
Volume 22, Issue 2
May and June 2022
Pages 125-144