Numerical model for a single pile with negative friction and soil consolidation
YANG Jun, ZHANG Dafeng
Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education of China, Department of Civil Engineering, Tsinghua University, Beijing 100084, China
Abstract：This paper describes a numerical model for predicting the pile foundation conditions with negative friction and soil consolidation. The geotechnical finite element software Plaxis was used to create the numerical model and soil replacement method to simulate initial soil state before acceleration of the centrifuge. Then, the development of negative friction was simulated, and the results are quite accurate. The predicted soil settlement error after consolidation is within 6.8% of the test data, the pile settling error is within 34.7% and the piling force error is within 18.3%. In addition, the excess pore pressure and relative maximum axial piling force are consistent with centrifuge test data for various consolidation times and axial force is approximately linearly related with the square root of time. This model provides reference data for calculating single pile foundations with negative friction and soil consolidation.
杨军, 张大峰. 考虑固结过程的单桩负摩擦数值模型[J]. 清华大学学报（自然科学版）, 2015, 55(12): 1276-1280.
YANG Jun, ZHANG Dafeng. Numerical model for a single pile with negative friction and soil consolidation. Journal of Tsinghua University(Science and Technology), 2015, 55(12): 1276-1280.
[1] Fellenius B H. Results from long-term measurement in piles of drag load and downdrag [J]. Canadian Geotechnical Journal, 2006, 43(4): 409-430.
[2] 周景星. 基础工程 [M]. 北京: 清华大学出版社, 2007: 143-150. ZHOU Jingxin. Foundation Engineering [M]. Beijing: Tsinghua University Press, 2007: 143-150.
[3] Bjerin L. Negative Skin Friction on Long Precast Piles Driven in Clay [R]. Stockholm, Swedish: Swedish Geotechnical Institute, 1977.
[4] GB 50112-2013. 膨胀土地区建筑技术规范 [S]. 北京: 中国建筑工业出版社, 2012.GB 50112-2013. Technical Code for Buildings in Expansive Soil Regions [S]. Beijing: China Architecture & Building Press, 2012.
[5] Fellenius B H. Negative skin friction and settlement of piles [C]// Second International Seminar, Pile Foundations. Singapore: Nanyang Technological Institute, 1984: 12.
[6] LIU Jinyuan, GAO Hongmei, LIU Hanlong. Finite element analyses of negative skin friction on a single pile [J]. Acta Geotechnica, 2012, 7(3): 239-252.
[7] Lam S Y, Ng C W, Leung C F, et al. Centrifuge and numerical modeling of axial load effects on piles in consolidating ground [J]. Canadian Geotechnical Journal, 2009, 46(1): 10-24.
[8] Ng C W, Poulos H G, Chan V S, et al. Effects of tip location and shielding on piles in consolidating ground [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2008, 134(9): 1245-1260.
[9] 徐长节, 耿雪玉, 蔡袁强. 任意荷载下欠固结地基的非线性一维固结 [J]. 岩土力学, 2006(03): 389-394.XU Changjie, GENG Xueyu, CAI Yuanqiang. One-dimensional nonlinear consolidation of under consolidation clay under arbitrary loadings [J]. Rock and Soil Mechanics, 2006(03): 389-394.
[10] Brinkgreve R B J. PLAXIS 2D 2011 . (2013- 05-01), http://www.plaxis.nl/.
[11] WANG Rui, Brandenberg S J. Beam on nonlinear Winkler foundation and modified neutral plane solution for calculating downdrag settlement [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2013, 139(9), 1433-1442.
2015, Vol. 55 
