Numerical study of the bearing capacity of the foundation adjacent to the clay slope reinforced with a stone column

Document Type : Research Paper

Authors

1 Assistant Professor, Department of Civil Engineering, Faculty of Engineering, Hormozgan University, Bandar Abas, I. R. Iran.

2 MSc Student, Uinversity of Hormozgan

Abstract

Soft and loose soils have always been the focus of attention due to their high settlement and insufficient bearing capacity. The foundations on soft soils and soil slopes containing this type of soil should be modified for high probability of failure. There are various ways to improve these soils, which vary greatly depending on the environmental conditions, site priority, the degree of softness, cost of materials used. Stone column is one of soft soil modification and soil slopes safety factor improvement methods which is economical and easy to implement. The aim of this study is to conduct a numerical study to investigate the effect of stone columns on the bearing capacity of the clay slope and its stability using the FLAC3D finite difference software. the slope is modeled in three dimensions with appropriate dimensions and boundary conditions. The bearing capacity was obtained by stress control procedure and slope safety factor was calculated by shear strength reduction method. In general, two types of failures observed in stone columns. The columns were Located under the footing Were exposed to phenomenon of bulging and the columns were Located outside the footing Were exposed to phenomenon of lateral displacement. The results showed that in general, the stone column will improve the stability of clay slope and its bearing capacity. The use of stone column below the foundation will affect the most on increasing bearing capacity and the effect will decrease by increasing center to the center distance of foundation and columns, so that at 4 times the diameter of stone column it will not have much effect on the bearing capacity. In the case of group columns, the arrangements are along the length of footing is preferred over the arrangements are along slope due to the higher replacement area.

Keywords

Main Subjects


Al-Shukur, A. K. 2015. “Stability analysis of side slope by using stone column and tieback support”. Int. J. Sci. Eng. Res., 5(9): 1837-1844.
Ambily, A. P. and Gandhi, S. R. 2007. “Behavior of stone columns based on experimental and FEM analysis”. Geotech. Geoenviron. Eng., ASCE, 133(4): 405-415.
Andreou, P. and Papadopoulos, V. 2006. “Modelling stone columns in soft clay”. Numer. Meth. Geotech. Eng., 32(4): 82-93.
Balaam, N. P. and Booker, J. R. 1985. “Effect of stone column yield on settlement of rigid foundations in stabilized clay”. Int. J. Numer. Anal. Meth. Geomech., 9(4): 331-351.
Castro, J. 2017. “Groups of encased stone columns: Influence of column length and arrangement”. Geotext. Geomembranes, 45(2): 68-80.
Deb, K., Samadhiya N. K. and Namdeo, J. B .2011. “Laboratory model studies on unreinforced and geogrid-reinforced sand bed over stone column-improved soft clay”. Geotext. Geomembranes, 29(2): 190-196.
Fattah, M. Y., Al-Neami, M. A. and Al-Suhaily, A. S. 2017. “Estimation of bearing capacity of floating group of stone columns”. Eng. Sci. Technol., 20(3): 1166-1172.
Geotechnical Design Manual. 2010. M 46-03.03, Chapter 7, p. 4, Washington State Department of Transportation.
Ghazavi, M. and Nazari Afshar, J. 2013. “Bearing capacity of geosynthetic encased stone columns”. Geotext. Geomembranes, 38(1): 26-36.
Haji Azizi, M. and Nasiri, M. 2019. “Experimental and numerical investigation on stability of sandy slope reinforced by using geotextile reinforced stone column”. J. Ferdowsi Civ. Eng., 52(1): 85-100.
Hughes, J. M. O. and Withers, N. J. 1974. “Reinforcing of soft cohesive soils with stone columns”. Ground Eng., 7(3): 42-49.
Kadhim, S., Parsons, R. L and Han, J. 2015. “Stability analysis of embankments supported by geosynthetic encased stone columns”. Geotech. Special Pub., 3(1): 2318-2327.
Lajevardi, S. H., Enami, S., Shamsi, H. R. and Hamidi, M. 2019. “Experimental study of single and groups of stone columns encased by geotextile”. Amir Kabir J. Civ. Eng., 50(6): 337-346.
Murugesan, S. and Rajagopal, K. 2010. “Studies on the behavior of single and group of geosynthetic encased stone columns”. J. Geotech. Geoenviron. Eng., 136(1): 129-139.
Naderi, E., Asakereh, A. and Dehghani, M. 2018. “Bearing capacity of strip footing on clay slope reinforced with stone columns”. Arab. J. Sci. Eng., 43(10): 5559-5572.
Raee, E., Hataf, N., Barkhordari, K. and Ghahramani, A. 2019. “The effect of rigidity of reinforced stone columns on bearing capacity of strip footings on the stabilized slopes”. Int. J. Civ. Eng., 17(6): 673-685.
Sivakumar, V. and Black, J. A. 2007. “A laboratory model study of the performance of vibrated stone columns in soft clay”. In: Proceedings of the 14th European Conference on Soil Mechanics and Geotechnical Engineering, Madrid, pp. 1053-1062.
Vekli, M., Aytekin, M., Banu­ ─░kizler, S. and Çalik, Ü. 2012. “Experimental and numerical investigation of slope stabilization by stone columns”. Nat. Hazards, 64(1): 797-820.
Wei, W. B. and Cheng, Y. M. 2009. “Strength reduction analysis for slope reinforced with one row of piles”. Comp. Geotech., 36(1): 1176-1185.