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浙江大学学报(工学版)
Journal of ZheJiang University (Engineering Science)  2020, Vol. 54 Issue (4): 739-747    DOI: 10.3785/j.issn.1008-973X.2020.04.013
Civil Engineering, Traffic Engineering     
Internal force and deformation of step-tapered pile under lateral loads
Wen-tao HU1(),Dou LIU1,Da-xin GENG4,*(),Ning WANG1,Chang-jie XU1,2,Xing SHANGGUAN1,Jie MIN3
1. Jiangxi Key Laboratory of Infrastructure Safety Control in Geotechnical Engineering, East China Jiaotong University, Nanchang 330013, China
2. Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China
3. Jiangxi Vocational College of Environmental Engineering, Ganzhou 341000, China
4. National Experimental Teaching Demonstration Center of Civil Engineering, East China Jiaotong University, Nanchang 330013, China
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Abstract  

An analytical algorithm for calculating the lateral response of a horizontally loaded step-tapered pile was proposed based on linear elastic subgrade reaction theory. The algorithm assumes a constant subgrade reaction modulus for each soil layer. The pile was segmented according to the variation in the pile section and the different soil layers. The governing equation for every segment was established. Then the iterative relationship of the deflection was derived, and the distribution of internal force and deformation of the pile with given boundary conditions were given by considering the deformation continuity between the adjacent pile segments and the boundary conditions of the pile tips. The obtained results were compared with the finite element calculation results and the field measured data in order to verify the algorithm. The influences of pile parameters such as length-diameter ratio, the position of the reduced diameter or pile-diameter ratio on the internal force and deformation distribution of pile were discussed. Reducing the length-diameter ratio and shifting the position of the reduced diameter to the bottom of the pile can reduce the maximum groundline displacement and increase the maximum bending moment. Reducing the pile-diameter ratio is conducive to reducing the maximum bending moment and coordinating the deformation more effectively.

Key words： step-tapered pile      length-diameter ratio      position of tapered section      pile-diameter ratio      horizontal bearing capacity     
Received: 14 January 2019      Published: 05 April 2020
CLC:  TU 443  
Corresponding Authors: Da-xin GENG     E-mail: qqzei@outlook.com;gengdaxin@ecjtu.edu.cn
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Wen-tao HU
Dou LIU
Da-xin GENG
Ning WANG
Chang-jie XU
Xing SHANGGUAN
Jie MIN
Cite this article:

Wen-tao HU,Dou LIU,Da-xin GENG,Ning WANG,Chang-jie XU,Xing SHANGGUAN,Jie MIN. Internal force and deformation of step-tapered pile under lateral loads. Journal of ZheJiang University (Engineering Science), 2020, 54(4): 739-747.

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http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2020.04.013     OR     http://www.zjujournals.com/eng/Y2020/V54/I4/739


水平受荷阶梯形变截面桩的内力及变形分析

基于线弹性地基反力法，提出水平荷载作用下阶梯形变截面桩内力及变形解析算法，该算法假定相同土层的地基反力模量为常数. 根据桩身的变截面特性以及桩周土体的分层情况将桩身进行分段，建立各段的微分控制方程. 考虑到桩顶、桩端边界条件以及相邻桩段间的协调变形条件，推导出符合桩段挠曲变形特征的迭代关系，得到任意边界条件下的桩身内力及变形算法. 通过将该算法的预测结果与有限元计算结果以及现场实测数据进行对比分析，验证了该方法的可行性. 分析桩身长径比、变径位置、桩径比对桩身内力及变形分布的影响规律. 减小长径比,将变径位置向桩底下移，均可以使得桩顶最大水平位移减小，最大弯矩增大，减小下部桩径有利于减小桩身弯矩峰值，更有效地协调桩身变形.


关键词： 阶梯形变截面桩,  长径比,  变径位置,  桩径比,  水平承载力 
Fig.1 Subdividing of section varied pile under lateral load
Fig.2 Calculation flow chart for response of horizontally loaded step-tapered piles
Fig.3 Modulus of subgrade reaction around pile
Fig.4 Computed horizontal displacement contrast with numerical results and field test results
Fig.5 Computed bending moment contrast with numerical results and measurement results
土体类别 t/m v Es /kPa Esoil /kPa
中密砂 4 0.3 22 900 17 011.3
粉砂 1 0.3 29 840 22 166.86
Tab.1 Soil parameters in Ismael[1]
Fig.6 Computed bending moment contrast with numerical results and field test results
L/D D d d/D 变径位置
10 1 0.6 0.6 40%
12 0.83 0.5 0.6 40%
14 0.7 0.42 0.6 40%
16 0.625 0.375 0.6 40%
18 0.55 0.33 0.6 40%
20 0.5 0.3 0.6 40%
20 0.5 0.3 0.6 20%
20 0.5 0.3 0.6 40%
20 0.5 0.3 0.6 60%
20 0.5 0.3 0.6 80%
20 0.5 0.25 0.5 40%
20 0.5 0.3 0.6 40%
20 0.5 0.35 0.7 40%
20 0.5 0.4 0.8 40%
20 0.5 0.45 0.9 40%
20 0.5 0.5 1.0 40%
Tab.2 Pile parameters under different conditions
Fig.7 Influence of length-diameter ratio on displacement
Fig.8 Influence of length-diameter ratio on moment
Fig.9 Influence of location of discontinuity in diameter on displacement
Fig.10 Influence of location of discontinuity in diameter on moment
Fig.11 Influence of butt diameter to tip diameter on displacement
Fig.12 Influence of butt diameter to tip diameter on moment
[1]   ISMAEL N F Behavior of step tapered bored piles in sand under static lateral loading[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2010, 136 (5): 669- 676
doi: 10.1061/(ASCE)GT.1943-5606.0000265
[2]   张玲, 赵明华, 赵衡 双层地基水平受荷桩受力变形分析[J]. 岩土力学, 2011, 32 (Suppl.2): 302- 305
ZHANG Ling, ZHAO Ming-hua, ZHAO Heng Analysis of the deformation of the horizontally loaded piles on the double-layered foundation[J]. Rock and Soil Mechanics, 2011, 32 (Suppl.2): 302- 305
[3]   ZHANG L, ZHAO M, ZOU X Behavior of laterally loaded piles in multilayered soils[J]. International Journal of Geomechanics, 2015, 15 (2): 06014017
doi: 10.1061/(ASCE)GM.1943-5622.0000319
[4]   GABR M A, LUNNE T, POWELL J J Analysis of laterally loaded piles in clay using DMT[J]. Journal of Geotechnical Engineering, 1994, 120 (5): 816- 837
[5]   SHATNAWI E, LIANG R Y, NUSAIRAT J Hyperbolic P-Y criterion for cohesive soils[J]. Jordan Journal of Civil Engineering, 2007, 1 (1): 38
[6]   王国粹, 杨敏 砂土中水平受荷桩非线性分析[J]. 岩土力学, 2011, (Suppl.2): 261- 267
WANG Guo-cui, YANG Min Sandy soil nonlinear analysis of horizontally loaded piles[J]. Rock and Soil Mechanics, 2011, (Suppl.2): 261- 267
[7]   SUITS L D, SHEAHAN T C, YANG K, et al Methods for deriving p-y curves from instrumented lateral load tests[J]. Geotechnical Testing Journal, 2013, 30 (1): 31- 38
[8]   YIN P, HE W, YANG Z J A simplified nonlinear method for a laterally loaded pile in sloping ground[J]. Advances in Civil Engineering, 2018, (5): 1- 9
[9]   尹平保, 聂道流, 杨朝晖, 等 斜坡基桩p-y曲线及水平承载计算方法研究[J]. 岩石力学与工程学报, 2018, 37 (4): 996- 1003
YIN Ping-bao, NIE Dao-liu, YANG Chao-hui, et al Study on calculation method of p-y curve and horizontal load of slope foundation piles[J]. Chinese Journal of Rock Mechanics and Engineering, 2018, 37 (4): 996- 1003
[10]   POULOS H G, DAVIS E H. Pile foundation analysis and design [M]. [S.l.]: Wiley, 1980: 472-473.
[11]   REESE L C Laterally loaded piles: program documentation[J]. Journal of Geotechnical and Geoenvironmental Engineering, 1977, 103 (12): 287- 305
[12]   MATLOCK H, REESE L C Generalized solutions for laterally loaded piles[J]. Geotechnical Special Publication, 1960, 127 (118): 1220- 1248
[13]   TEHRANI F S, SALGADO R, PREZZI M. A semi-analytical solution for laterally loaded pile groups in multilayered soils [C]//European Conference on Soil Mechanics and Geotechnical Engineering. Edinburgh: [s.n.], 2015.
[14]   ZHAO Heng, YIN Ping-bao, LI Xi-bing Mechanical response of bridge piles in high-steep slopes and sensitivity study[J]. Journal of Central South University: English Edition, 2015, 22 (10): 4043- 4048
doi: 10.1007/s11771-015-2948-1
[15]   赵明华, 杨超炜, 杨明辉, 等 基于有限杆单元法的陡坡段桥梁基桩受力分析[J]. 中国公路学报, 2014, 27 (6): 51- 58
ZHAO Ming-hua, YANG Chao-wei, YANG Ming-hui, et al Mechanical analysis of piles on steep slopes based on finite element method[J]. China Journal of Highway and Transport, 2014, 27 (6): 51- 58
doi: 10.3969/j.issn.1001-7372.2014.06.007
[16]   赵明华, 刘涛, 杨超炜, 等 考虑陡坡效应的横向受荷桩受力分析纽玛克解答[J]. 公路交通科技, 2014, 31 (10): 58- 64
ZHAO Ming-hua, LIU Tao, YANG Chao-wei, et al Stress analysis of laterally loaded piles taking into account the effect of steep slopes Newmark's solution[J]. Journal of Highway and Transportation Research and Development, 2014, 31 (10): 58- 64
doi: 10.3969/j.issn.1002-0268.2014.10.010
[17]   MCCLELLAND B Soil modulus for laterally loaded piles[J]. Soil Mechanics and Foundation Division, 1956, 82: 1- 22
[18]   RANDOLPH M F The response of flexible piles to lateral loading[J]. Geotechnique, 1981, 31 (2): 247- 259
doi: 10.1680/geot.1981.31.2.247
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