Investigating the Effect of Geocell Changes on Slope Stability in Unsaturated Soil

Document Type : Original Article

Authors

1 Department of Civil Engi-neering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.

2 Department of Civil Engi-neering, Najafabad Branch, Islamic Azad University, Najafabad, Iran

3 Civil Engineering Group, Is-fahan university of technol-ogy, Isfahan, Iran

4 Departeman of water and natural Environment, Isfahan Higher Education and Re-search Institute (IHEARI); Mimistry of Energy, Isfahan, Iran

10.22091/cer.2019.4270.1147

Abstract

The purpose of this research is to investigate the performance and efficiency of reinforced slope in the stability of geocell layers in unsaturated soil conditions. Slope reinforced with geocell, due to the fact that the geocell has a height (three-dimensional), acts as a beam in the soil, and because of its flexural properties, it has a moment of inertia as well as bending strength, which reduces the displacement and increases the coefficient reliability of the slope. Considering unsaturated conditions of soil contributes a lot to make results close to reality. One of the well-known models among elastoplastic mod-els for modeling unsaturated soils is Barcelona's basic model, which has been added to the FLAC2D software by codification. Changes in thickness, length, and the number of geocell layers are remarkably effective on slope stability. The results show that the geocell's reinforcing efficiency depends on the number of layers and the depth of its placement. As the depth of the geocell's first layer increases, the lateral and vertical side elevation of the upper part of the slope increases with respect to the elevation. Load capacity increases with increasing geocell length. By increasing the length of the geocell lay-er, the joint strength, the tensile strength of the mobilized, and the bending moment are increased. Also, by increasing the thickness of the geocell, the amount of moment of the inertia increases, and as a result, the amount of geocell reinforcement bending moment increases.

Keywords

Main Subjects

References

[1] Hegde, A. M., & Sitharam, T. G. (2015). “Three-dimensional numerical analysis of geocell-reinforced soft clay beds by considering the actual geometry of geocell pockets”, Canadian Geotechnical Journal, 52(9), 1396-1407.
[2] Skinner, G. D., & Rowe, R. K. (2005). “Design and behaviour of a geosynthetic reinforced retaining wall and bridge abutment on a yielding foundation”, Geotextiles and Geomembranes, 23(3), 234-260.
[3] Leshchinsky, B., & Ling, H. (2013). “Effects of geocell confinement on strength and deformation behavior of gravel”, Journal of Geotechnical and Geoenvironmental Engineering, 139(2), 340-352.
[4] Zornberg, J. G., & Arriaga, F. (2003). “Strain distribution within geosynthetic-reinforced slopes”, Journal of Geotechnical and Geoenvironmental Engineering, 129(1), 32-45.
[5] Belabed, L., Benyaghla, H., & Yahiaoui, J. (2011). “Internal stability analysis of reinforced earth retaining walls”, Geotechnical and geological engineering, 29(4), 443-452.
[6] Chen, R. H., & Chiu, Y. M. (2008). “Model tests of geocell retaining structures”, Geotextiles and Geomem-branes, 26(1), 56-70.
[7] Chen, R. H., Huang, Y. W., & Huang, F. C. (2013). “Confinement effect of geocells on sand samples under triaxial compression”, Geotextiles and Geomembranes, 37, 35-44.
[8] Fakher, A., & Jones, C. J. F. P. (2001). “When the bending stiffness of geosynthetic reinforcement is im-portant”, Geosynthetics International, 8(5), 445-460.
[9] Zhang, L., Zhao, M., Zou, X., & Zhao, H. (2009). “Deformation analysis of geocell reinforcement using Winkler model”, Computers and Geotechnics, 36(6), 977-983.
[10] Zhang, L., Zhao, M., Zou, X., & Zhao, H. (2010). “Analysis of geocell-reinforced mattress with considera-tion of horizontal–vertical coupling”, Computers and Geotechnics, 37(6), 748-756.
[11] Dash, S. K., Rajagopal, K., & Krishnaswamy, N. R. (2007). “Behaviour of geocell-reinforced sand beds under strip loading”, Canadian Geotechnical Journal, 44(7), 905-916.
[12] Yang, X., Han, J., Parsons, R. L., & Leshchinsky, D. (2010). “Three-dimensional numerical modeling of single geocell-reinforced sand”, Frontiers of Architecture and Civil Engineering in China, 4(2), 233-240.
[13] Roy, K., Hawlader, B., Kenny, S., & Moore, I. (2015). “Finite element modeling of lateral pipeline–soil in-teractions in dense sand”, Canadian Geotechnical Journal, 53(3), 490-504.
[14] Sheng, D. (2011). “Review of fundamental principles in modelling unsaturated soil behaviour”, Computers and Geotechnics, 38(6), 757-776.
[15] Sheng, D. (2011). “Constitutive modelling of unsaturated soils: Discussion of fundamental princi-ples”, Unsaturated soils, 1, 91-112.
[16] Uchaipichat, A. (2011). “Effective stress parameter of unsaturated granular soils”; International Confer-ence on Mechanical, Automobile and Robotics Engineering (ICMAR, 2011), 231-234.
[17] Fredlund, D. G., Morgenstern, N. R., & Widger, R. A. (1978). “The shear strength of unsaturated soils”, Canadian geotechnical journal, 15(3), 313-321.
[18] Yang, K. H., Thuo, J. N., Chen, J. W., & Liu, C. N. (2019). “Failure investigation of a geosynthetic-reinforced soil slope subjected to rainfall”, Geosynthetics international, 26(1), 42-65.
[19] Oberg, A. L., & Sallfors, G. (1995). “A rational approach to the determination of the shear strength parame-ters of unsaturated soils”, In Proceedings of the first international conference on unsaturated soils/ unsat'95/ Paris/ France, 1.
[20] Bolzon, G., Schrefler, B. A., & Zienkiewicz, O. C. (1996). “Elastoplastic soil constitutive laws generalized to partially saturated states”, Géotechnique, 46(2), 279-289.
[21] Wu, L. Z., Huang, R. Q., Xu, Q., Zhang, L. M., & Li, H. L. (2015). “Analysis of physical testing of rainfall-induced soil slope failures”, Environmental earth sciences, 73(12), 8519-8531.
[22] Khalili, N., & Khabbaz, M. H. (1998). “A unique relationship for χ for the determination of the shear strength of unsaturated soils”, Geotechnique, 48(5), 681-687.
[23] Alonso, E. E., Gens, A., & Josa, A. (1990). “A constitutive model for partially saturated soils”, Géotechnique, 40(3), 405-430.
[24] Sreedeep, S., & Singh, D. N. (2006). “Nonlinear curve-fitting procedures for developing soil-water character-istic curves”, Geotechnical Testing Journal, 29(5), 409-418.
[25] Van Genuchten, M. T. (1980). “A closed-form equation for predicting the hydraulic conductivity of un-saturated soils 1”, Soil science society of America journal, 44(5), 892-898.
[26] Cheng, Y. M., Lansivaara, T., & Wei, W. B. (2007). “Two-dimensional slope stability analysis by limit equi-librium and strength reduction methods”, Computers and geotechnics, 34(3), 137-150.
[27] Zhou, H., & Wen, X. (2008). “Model studies on geogrid-or geocell-reinforced sand cushion on soft soil”, Geotextiles and Geomembranes, 26(3), 231-238.
[28] Pokharel, S. K., Han, J., Leshchinsky, D., Parsons, R. L., & Halahmi, I. (2010). “Investigation of factors influencing behavior of single geocell-reinforced bases under static loading”, Geotextiles and Geomem-branes, 28(6), 570-578.
[29] Mehdipour, I., Ghazavi, M., & Moayed, R. Z. (2013). “Numerical study on stability analysis of geocell re-inforced slopes by considering the bending effect”, Geotextiles and Geomembranes, 37, 23-34.
[30] Zhao, M. H., Zhang, L., Zou, X. J., & Zhao, H. (2009). “Research progress in two-direction reinforced com-posite foundation formed by geocell reinforced mattress and gravel piles”, China Journal of Highway and Transport, 22(1), 1-10.
[31] Madhavi Latha, G., Rajagopal, K., & Krishnaswamy, N. R. (2006). “Experimental and theoretical investi-gations on geocell-supported embankments”, International Journal of Geomechanics, 6(1), 30-35.
Send comment about this article
CAPTCHA Image
Civil Infrastructure Researches
Volume 5, Issue 2 - Serial Number 9
March 2020
Pages 137-151

Files

Share

How to cite

Statistics