Analytical approach to evaluate stability of pile-stabilized slope

Document Type : Article


1 Department of Civil Engineering, Razi University, Kermanshah, Iran

2 Department of Civil Engineering, University of Ayatollah ozma Boroujerdi , Iran

3 Department of Civil & Environmental Engineering, University of Auckland, Auckland, New Zealand


Many studies have been conducted to examine the factor of safety of a slope reinforced by a row of piles and the forces acting on these piles. This paper presents an analytical approach to calculate the forces acting on piles and the corresponding factor of safety of slopes stabilized by a row of piles. The proposed approach is based on force equilibrium within the upslope wedge above the pile location and would require knowledge of the upper wedge weight before application. The validity of the proposed analytical approach was verified by comparing the results with those obtained using available approaches in the literature as well as from physical experiments and numerical analyses using available software. Additionally, the effect of arching phenomenon was examined and the optimum pile spacing for use in reinforcing slopes was investigated. The optimum pile spacing depends on the properties of the soil comprising the slope, but the most cost-effective pile spacing was found to be between 4-5 times of the pile diameter, corresponding to the largest spacing that can generate arching between piles. Thus, the proposed analytical approach can be used in practical applications to determine the stability of slopes reinforced by a row of piles.


Main Subjects

1. Ashour, M. and Ardalan, H. Analysis of pile stabilized
slopes based on soil-pile interaction", Computers and
Geotechnics, 39, pp. 85-97 (2012).
2. Ito, T., Matsui, T., and Hong, P.W. Design method
for stabilizing piles against landslide - one row of piles",
Soils and Foundations, 21(1), pp. 21-37 (1981).
3. Poulos, H.G. Design of reinforcing piles to increase
slope stability", Can. Geotech. J., 32(5), pp. 808-818
4. Chen, L.T. and Poulos, H.G. Piles subjected to lateral
soil movements", J. Geotech. Geoenviron Eng. ASCE,
123(9), pp. 802-811 (1997).
5. Zeng, S. and Liang, R. Stability analysis of drilled
shafts reinforced slope", Soils and Foundations, 42(2),
pp. 93-102 (2002).
6. Won, J., You, K., Jeong, S., and Kim, S. Coupled
e ects in stability analysis of pile-slope systems", Computers
and Geotechnics, 32(4), pp. 304-315 (2005).
7. Wei, W.B. and Cheng, Y.M. Strength reduction
analysis for slope reinforced with one row of piles",
Computers and Geotechnics, 36(7), pp. 1176-1185
8. Kourkoulis, R. and Gelagoti, F. Slope stabilizing
piles and pile-groups: parametric study and design insights",
J. Geotech. Geoenviron. Eng., ASCE, 137(7),
pp. 663-677 (2011).
9. Alkasawneh, W., Malkawi, A.H., Nusairat, J.H., and
Albataineh, N. A comparative study of various commercially
available programs in slope stability analysis",
Computers and Geotechnics, 35, pp. 428-435
10. Hassiotis, S., Chameau, J.L., and Gunaratne, M.
Design method for stabilization of slopes with piles",
J. Geotech. Geoenviron. Eng., ASCE, 123(4), pp. 314-
323 (1997).
11. Huang, C.C., Tsai, C.C., and Chen, Y.H. Generalized
method for three-dimensional slope stability analysis",
J. Geotech Geoenviron Eng, ASCE, 128(10), pp. 836-
848 (2002).
12. Huang, M., Wang, H., Sheng, D., and Liu, Y.
Rotational-translational mechanism for the upper
bound stability analysis of slopes with weak interlayer",
Computers and Geotechnics, 53, pp. 133-141
13. Chen, W.F. Limit analysis and soil plasticity", Elsevier
Scienti c Publishing Company, New York (1975).
14. Hajiazizi, M. and Tavana, H. Determining threedimensional
non-spherical critical slip surface in earth
slopes using an optimization method", Engineering
Geology, 153, pp. 114-124 (2013).
15. Ausilio, E., Conte, E., and Dente, G. Stability
analysis of slopes reinforced with piles", Computers
and Geotechnics, 28, pp. 591-611 (2001).
16. Nian, T.K., Chen, G.Q., Luan, M.T., Yang, Q.,
and Zheng, D.F. Limit analysis of the stability of
slopes reinforced with piles against landslide in nonhomogeneous
and anisotropic soil", Canadian Geotechnical
Journal, 45(8), pp. 1092-1103 (2008).
17. Liang, R.Y., Joorabchi, A.E., and Li, L. Design
method for drilled shaft stabilization of unstable
slopes", Geo-Congress 2013, ASCE, pp. 2024-2033
18. Cai, F. and Ugai, K. Numerical analysis of the
stability of a slope reinforced with piles", Soils and
Foundations, 40, pp. 73-84 (2000).
19. Michalowski, R.L. Stability charts for uniform
slopes", J. Geotech Geoenviron Eng, ASCE, 128(4),
pp. 351-355 (2002).
20. Tang, G., Zhao, L., Li, L., and Yang, F. Stability
charts of slopes under typical conditions developed by
upper bound limit analysis", Computers and Geotechnics,
65, pp. 233-240 (2015).
21. Ito, T. and Matsui, T. Methods to estimate lateral
force acting on stabilizing piles", Soils and Foundations,
15(4), pp. 43-59 (1975).
22. Kourkoulis, R., Gelagoti, F., Anastasopoulos, L., and
Gazetas, G. Hybrid method for analysis and design
of slope stabilizing piles", Journal of Geotechnical and
Geoenvironmental Engineering, ASCE, 138(1), pp. 1-
14 (2012).
23. Liang, R.Y. and Yamin, M.M. Three dimensional -
nite element study of arching behavior in slope/drilled
shafts system", Int J Numer Anal Methods Geomech,
34(11), pp. 1157-1168 (2010).
24. Lee, C.Y., Hull, T.S., and Poulos, H.G. Simpli ed
pile-slope stability analysis", Computers and Geotechnics,
17(1), pp. 1-16 (1995).
25. Li, X., He, S., and Wu, Y. Seismic displacement of
slopes reinforced with piles", Journal of Geotechnical
and Geoenvironmental Engineering, ASCE, 136(6),
pp. 880-884 (2010).
26. Broms, B. Lateral resistance of piles in cohesionless
soils", J. Soil Mech. Found. Div, 90(3), pp. 123-156
27. Kahyaoglu, M., Onal, O., and Imancl, G. Soil arching
and load transfer mechanism for slope stabilized with
piles", Journal of Civil Engineering and Management,
18(5), pp. 701-708 (2012).
28. GEO-SLOPE International Ltd. Stability Modeling
with SLOPE/W 2007: An Engineering Methodology,
4th Ed. Alberta, Canada (2015).
29. Steward, T., Sivakugan, N., Shukla, S.K., and Das,
B.M. Taylor's slope stability charts revisited", Int J
Geomech, 11(4), pp. 348-52 (2011).
2536 M. Hajiazizi et al./Scientia Iranica, Transactions A: Civil Engineering 25 (2018) 2525{2536
30. Hajiazizi, M. and Mazaheri, A.H. The use of the line
segments slip surface for location optimization of pile
in stabilization of earth slopes", International Journal
of Civil Engineering, 13(1), pp. 14-27 (2015).
31. Adachi, T., Kimura, M., and Tada, S. Analysis on the
preventive mechanism of landslide stabilizing piles",
Numerical Models in Geomechanics (NUMOG III),
Elsevier, pp. 691-698 (1989).
32. Plaxis. PLAXIS 2D Reference Manual. Delft, Netherlands
33. Boshcher, P.J. and Gray, D.H. Soil arching in sandy
slopes", J. Geotech. Engrg., ASCE, 112(6), pp. 626-
645 (1986).
34. Smethurst, J.A. and Powrie, W. Monitoring and
analysis of the bending behaviour of discrete piles used
to stabilise a railway embankment", Geotechnique,
57(8), pp. 663-677 (2007).
35. Liang, R. and Zeng, S. Numerical study of soil arching
mechanism in drilled shafts for slope stabilization",
Soils and Foundations, 42(2), pp. 83-92 (2002).
36. Plaxis. PLAXIS 3D Reference Manual, Delft, Netherlands
37. Poulos, H.G. Design of slope stabilizing piles", Slope
Stability Engineering, J.C. Jiang, N. Yagi, and T.
Yamagami, Eds., Balkema, Rotterdam, Netherlands