en Geotechnique Geotechnique Research Paper Research Paper A simplified approach for nonlinear analysis of the load-displacement response of a single pile and a pile group is presented using the load-transfer approach. A hyperbolic model is used to capture the relationship between unit skin friction and pile-soil relative displacement developed at the pile-soil interface and the load-displacement relationship developed at the pile end. As to the nonlinear analysis of the single pile response, a highly effective iterative computer program is developed using the proposed hyperbolic model. Furthermore, determinations of the parameters related to the hyperbolic model of an individual pile in a pile group are obtained considering interactions between piles. Based on the determinations of the parameters presented in the hyperbolic model of an individual pile in a pile group and the proposed iterative computer program developed for the analysis of the single pile response, the conventional load-transfer approach can then be extended to the analysis of the load-settlement response of an arbitrary pile in a pile group. Comparisons of the load-settlement response demonstrate that the proposed method is generally in good agreement with the field-observed behavior and the calculated results derived from other approaches. Single pile, Pile group, Skin friction, End resistance, Settlement, A hyperbolic model 146 159 http://ijce.iust.ac.ir/browse.php?a_code=A-10-1805-1&slc_lang=en&sid=1 Q. Q. Zhang zhangqq@sdu.edu.cn 180031947532846009390 180031947532846009390 Yes Ph.D (Corresponding Author), Geotechnical and Structural Engineering Research Center, Shandong University, Jinan, China; Key Laboratory of Geotechnical and Underground Engineering (Tongji University), Ministry of Education, Shanghai, China; State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, China Sh. C. Li zqq5820948@126.com 180031947532846009391 180031947532846009391 No Professor, Geotechnical and Structural Engineering Research Center, Shandong University, Jinan, China F. Y. Liang 180031947532846009392 180031947532846009392 No Professor, Key Laboratory of Geotechnical and Underground Engineering (Tongji University), Ministry of Education, Shanghai, China M. Yang 180031947532846009393 180031947532846009393 No Professor, Key Laboratory of Geotechnical and Underground Engineering (Tongji University), Ministry of Education, Shanghai, China Q. Zhang 180031947532846009394 180031947532846009394 No Ph.D. Candidate, Geotechnical and Structural Engineering Research Center, Shandong University, Jinan, China