Bearing Capacity of Strip Footings in various Locations with Respect to Sloping Ground

Document Type : پژوهشی

Author

• maryam haghbin

azad university of Islamshahr

10.22067/civil.v29i2.45069

Abstract

The purpose of footing design is transferring structure load to soil without causing shear failure and extra settlement in soil. Therefore, footing bearing capacity should be considered in various projects. In special case, footings are placed in various positions with respect to slope ground and position of ground slope affects footing bearing capacity. In fact, slope affects failure surface of soil beneath the foundation remarkably and therefore, footing location with respect to slope must be cared to determine exact footing bearing capacity. In present paper, analytical method is presented based on soil stability beneath the footing. Virtual retaining wall method is used in present study and by applying equilibrium between active and passive forces on virtual wall, footing bearing capacity on reinforced and unreinforced soils is determined in various positions with respect to slope ground. Also, varied parameters include soil resistance, footing spacing with respect to slope ground, width and depth of foundation and seismic coefficient. Results indicate, in various depths and widths of foundation, bearing capacity of footing on flat ground is more than top of slope and bearing capacity of footing top of slope is more than down of slope. Also, bearing capacity of footing on slope is minimum. Based on proposed method, footing location with respect to slope affects passive and active force on virtual retaining wall and footing bearing capacity remarkably. Also, the proposed method can determine effect of slope angle and reinforcement on footing bearing capacity. Presented method indicates effective distance from slope crest is almost 4.5B. Finally, the predicted results are compared with those reported from analytical and experimental methods performed by others, indicating an acceptable agreement.

Keywords

• Footing Bearing Capacity
• Slope Ground, Seismic Coefficient
• Footing Spacing, Depth and Width of Footing

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References

1. Meyerhof, G. G., "Some Recent Research on the Bearing Capacity of Foundations", Canadian Geotechnical Journal, Vol.1(1), pp. 16-27, (1963).

2. Meyerhof, G. G., "The Ultimate Bearing Capacity of Foundations on Slopes", Proceeding of IV International Conference on Soil Mech. Found. Eng., Vol.1, London, England, pp. 384-390, (1957).

3. Hansen, J. B., "A Revised and Extended Formula for Bearing Capacity", Bulletin 28.Copenhagen, Danish Geotechnical Institute, (1970).

4. Vesic, A. S., "Bearing Capacity of Shallow Foundations", Foundation Engineering Handbook, ed. H. F. Winterkorn and H. Y. Fang, 121. New York: Van Nostrand Reinhold Co, (1975).

5. Saran, S., Sud, V.K. and Handa, S. C., "Bearing Capacity of Footings Adjacent to Slopes", Journal of Geotechnical Engineering., ASCE, Vol. 115(4), pp. 553-564, (1989).

6. Bransby MF., Davidson C., "The Effect of Foundation Fixity on Their Capacity Adjacent to Slopes", Proceedings of the BGA International Conference on Foundations, Dundee, Scotland IHS BRE Press, (2008).

7. Gemperline, M. C., "Centrifuge Modeling of Shallow Foundations", in Proceeding ASCE Spring Convention, (1988).

8. Graham, J., Andrews. M., and Shields. D.H., "Stress Characteristics for Shallow Footings in Cohesionless Slopes", Canadian Geotechnical Journal, Vol. 25(2), pp. 238-245, (1988).

9. Choudhury, D and Rao, S., "Seismic Bearing Capacity of Shallow Strip Footings Embedded in Slope", International Journal of Geomechanics, pp. 176-184, (2006).

10. Shiau, S, Merifield, R. S , Lyamin, A. V. and Sloan, A. W., "Undrained Stability of Footings", International Journal of Geomechanics, pp. 381-390, (2011).

11. De Buhan, P., and Garnier, D, "Three Dimensional Bearing Capacity Analysis of a Foundation Near a Slope", Soils Foundation Journal, Vol. 38( 3), pp. 153–16, (1998).

12. Shields, D., Chandler, N., and Garnier, J., "Bearing Capacity of Foundations in Slopes", Journal of Geotechnical Engineering, Vol. 116(3), pp. 528–537, (1990).

13. Sawwaf., M., "Behaviour of Strip Footing on Geogrid Reinforced Sand over a Soft Clay Slope", Geotextiles and Geomembranes, Vol. 25, pp. 50-60, (2007).

14. Huang C.C and Tatsuoka .F & Sato., "Failure Mechanisms of Reinforced Sand Slopes Loaded with a Footing", Soils and Foundations Journal, Vol. 34(2), pp. 27-40, (1994).

15. Selvadurai and Gnanendran C. T., "Bearing Capacity of Foundation Near Slopes with Multi Layers of Geosynthetic", Indian Geotechnical Conference, pp. 14 -16, (2006).

16. Sarma, S. and Chen, Y.C., "Seiemic Bearing Capacity of Shallow Strip Footings Near Sloping Ground", 5th conference of European Seismic Design Practice, Research and Application, ed. Elnashai., Chester, UK, AA Balkema, Rotterdam, pp. 505-512, (1995).

17. Castelli, F. and Lentini, V., "Evaluation of the Bearing Capacity of Footings on Slopes", International Journal of Physical Modelling in Geotechnics, Vol. 12(3), pp. 112–118, (2012).

18. Castelli, F and Lentini, V., "Bearing Capacity of Shallow Foundations on Slope", Physical Modelling in Geotechnics, Balkema, Rotterdam, the Netherlands, pp. 685–690, (2010).

19. Castelli, F and Motta, E., "Bearing Capacity of Shallow Foundations Near Slopes: Static Analysis." Foundations Proceedings of the 2nd International British Geotechnical Association Conference on Foundations, BRE Press, Watford, UK, Vol. 1, pp. 1651–1662, (2008).

20. Castelli, F and Motta, E., "Bearing Capacity of Strip Footings Near Slopes", Journal Geotechnical and Geological Engineering, Vol. 28(2), pp. 187–198, (2010).