A simplified approach for evaluation of seismic displacements of pile group located in soil slope

Document Type : Research

Authors

1 Graduate researcher, master’s degree, faculty of civil engineering, University of Science and Culture, Tehran, Iran.

2 Assistant professor, faculty of civil engineering, University of Science and Culture, Tehran, Iran.

3 Assistant professor, faculty of civil engineering, Iran University of Science and Technology, Tehran, Iran.

Abstract

Seismically induced slope movements have imposed severe damage on the pile-supported structures located on soil slopes during past earthquakes. Consequently, evaluation of the lateral seismic response of pile-slope systems is an important measure towards safe design of pile groups. However, since the codes and techniques used in seismic design of pile groups for engineering purposes are neither practical nor easily accessible, it is difficult to employ them consistently in design procedures. Therefore, simplified approaches are required for pile design application. This paper presents a novel approach that practitioners can use to quickly evaluate the seismic displacements of pile-groups in soil slope. Such an approach is based on the reasonable and practical relationship found between the pseudo-static safety factor of pile-slope system and seismic displacements of pile groups. In order to explore this relationship, a parametric study was performed and a dimensional analysis was carried out to study  the results of the relationship and achieve the dimensionless chart. Thus, the conclusions of this study are intended to provide practitioners with some practical guidelines such as low calculation efforts, and to incorporate the relationship between slope safety factor and pile group displacements into the design process.

Keywords


  1.  Padron LA, Aznarez JJ, Maeso O. Dynamic analysis of piled foundations in stratified soils by a BEM-FEM model. Soil Dyn Earthq Eng 2008;28(5):333-346. [DOI:10.1016/j.soildyn.2007.07.005]
  2.  Wilson DW. (1998) "Soil-pile superstructure interaction in liquefying sand and soft clay".PhD thesis, Dept.Civ.Env.Engrg, University of California at Davis, California.
  3.  Hayward T, Lees AS, Powrie W, Richards DJ, Smethurst J. (2000), "Centrifuge modeling of a cutting slope stabilized by discrete piles", 105 Technical Report, Transport Research Library, Crothorne, UK, 32p.
  4. Chen L.T., Poulos H.G. (2001), "Approximation of lateral soil movements for analyzing lateral pile response", in Annual Conference of the Hong Kong Institution of Engineers.
  5.  Mezazigh, S., Levacher, D. (1998). "Laterally loaded piles in sand: Slope effect on p-y reaction curves." Can. Geotech. J., 35, 433-441. [DOI:10.1139/t98-016]
  6.  Rathje E.M. and Bray J.D. (2000), "Nonlinear coupled seismic sliding analisis of earth structures", Journal of Geotechnical and Geoenvironmental Engineering, Vol. 126, No. 11, pp. 1002-1014. [DOI:10.1061/(ASCE)1090-0241(2000)126:11(1002)]
  7.  Wartman J., Seed R. B., Bray J. D. (2005), "Shaking Table Modeling of Seismically Induced Deformations in Slopes", Journal of Geotechnical and Geoenvironmental Engineering, Vol. 131, No. 5, pp. 610-622. [DOI:10.1061/(ASCE)1090-0241(2005)131:5(610)]
  8.  Newmark, N.M. (1965), "Effects of Earthquakes on Dams and Embankments", Geotechnique, Vol. 15, No. 2 , pp. 139-159. [DOI:10.1680/geot.1965.15.2.139]
  9.  Abghari, A., and Chai, J. _1995_. "Modeling of soil-pile superstructure interaction for bridge foundations." Performance of deep foundations under seismic loading, J. P. Turner, ed., ASCE, N.Y., 45-59.
  10.  Liyanapathirana, D. S., and Poulos, H. G. _2005_. "Pseudostatic approach for seismic analysis of piles in liquefying soil." J. Geotech. Geoenviron. Eng., 131_12_, 1480-1487. [DOI:10.1061/(ASCE)1090-0241(2005)131:12(1480)]
  11.  Poulos, H. G. _2006_. "Ground movements-A hidden source of loading on deep foundations." Proc., Int. Conf. on Piling and Deep Foundations, J. Lindenberg, M. Bottiau, A. F. Van Tol, Amsterdam, The Netherlands, 2-19.
  12.  Novak, M. _1974_. "Dynamic stiffness and damping of piles." Can. Geotech.J., 11, 574-598. [DOI:10.1139/t74-059]
  13.  Makris, N., and Gazetas, G. _1992_. "Dynamic pile-soil-pile interaction. Part II: Lateral and seismic response." Earthquake Eng. Struct. Dyn. 21, 145-162. [DOI:10.1002/eqe.4290210204]
  14.  Tabesh A, Poulos HG.(2001)."Pseudostatic approach for seismic analysis of single piles". J GeotechGeoenvironEng, ASCE; 127(9):757-765. [DOI:10.1061/(ASCE)1090-0241(2001)127:9(757)]
  15.  Elahi H., Moradi M., Poulos H.G., Ghalandarzadeh A. (2010a). "Pseudostatic approach for seismic analysis of pile group", Computers and Geotechnics; 37:25-39. [DOI:10.1016/j.compgeo.2009.07.001]
  16.  Bray,J ., Travasarou, T ., "Pseudostatic Coefficient for Use in Simplified Seismic Slope Stability Evaluation" ., Journal of Geotechnical and Geoenvironmental Engineering ., ASCE,2009.135:1336-1340. [DOI:10.1061/(ASCE)GT.1943-5606.0000012]
  17.  Kramer SL. 'Geotechnical Earthquake Engineering." Prentice-Hall, Inc., Upper Saddle River, New Jersey 07458, 1996, pp. 434-437.
  18.  Terzaghi, K, (1950), Mechanics of Landslides, Engineering Geology (Berkey) Volume, Geological Society of America
  19.  Griffiths DV. Finite element analyses of walls, footings, and slopes. PhD Thesis, University of Manchester; 1980.
  20.  Chen L.T., Poulos H.G. (2001), "Approximation of lateral soil movements for analyzing lateral pile response", in Annual Conference of the Hong Kong Institution of Engineers.
  21.  FLAC, Fast Lagrangian analysis of continua, version 3.00, Itasca Consulting Group; 2002.
  22.  McCullough.N.J., Schlechter., M., Dickenson., E., Bloand.C., "Influence of Batter Piles on the Dynamic Behavior of Pile-Supported Wharf Structures", Proc. Ports 2004: Port Development in the Changing World, pp. 1-10. [DOI:10.1061/40727(2004)12]
  23.  Lu, J. (2006). "Parallel Finite Element Modeling of Earthquake Ground Response and Liquefaction" Ph.D. Dissertation, Univ. of California, San Diego.