开挖条件下黏土中单桩竖向承载特性模型试验与分析

纠永志; 黄茂松

doi:10.11779/CJGE201602002

开挖条件下黏土中单桩竖向承载特性模型试验与分析 English Version

纠永志^{1, 2, 3},
黄茂松^1,2,

1. 同济大学地下建筑与工程系,上海 200092; 2. 同济大学岩土及地下工程教育部重点实验室,上海 200092; 3. 中原工学院建筑工程学院,河南郑州 450007

基金项目: 国家重点基础研究发展计划（973计划）项目（2013CB036304）

详细信息

作者简介:
纠永志(1982- ),男,博士,从事岩土工程方面的科研和教学工作。E-mail: jyz912@163.com。

通讯作者:
黄茂松

计量
- 文章访问数: 397
- HTML全文浏览量: 1
- PDF下载量: 444
出版历程
- 收稿日期: 2015-01-05
- 发布日期: 2016-02-24

Studies on pile bearing characteristics in saturated clay under excavation by model tests and a simplified method

JIU Yong-zhi^{1, 2, 3},
HUANG Mao-song^1,2,

1. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; 2. Key Laboratory of Geotechnical and Underground Engineering of Ministy of Education, Tongji University, Shanghai 200092, China; 3. School of Civil Engineering and Architecture, Zhongyuan University of Technology, Zhengzhou 450007, China

摘要

摘要: 利用已有的离心机预固结加荷装置,开发了一套可以有效控制超固结比的模型桩竖向加荷系统,进行了开挖条件下饱和黏土中单桩竖向承载特性的室内模型试验。在模型试验用高岭土单元体试验的基础上,考虑开挖引起土体K₀系数和不排水抗剪强度变化对桩侧极限摩阻力的影响,提出了开挖卸荷条件下饱和黏土中单桩竖向承载特性的非线性简化计算方法,并通过与模型试验结果进行对比验证了计算方法的正确性,算例分析表明：开挖将会使得竖向桩顶刚度和极限承载力的降低,合理的预测方法应该既要考虑开挖卸荷引起的桩侧土上覆压力的减少,又要考虑桩侧土体K₀值和不排水抗剪强度的提高。
- 模型试验 /
- 开挖 /
- 极限承载力 /
- 抗剪强度 /
- 超固结比
Abstract: Based on a centrifuge pre-consolidation loading device, a model of pile vertical loading system can effectively control over consolidation ratio is developed out. The laboratory model tests of a single pile in saturated clay under excavation are carried out. Based on the results of model test, considering the change of undrained shear strength and K₀ coefficient of soil caused by excavation, a simplified nonlinear approach for analysis of a single pile under excavation is proposed. Calculated results are compared with the test results of laboratory model tests of pile. Good agreement is achieved. In addition, responses of a single pile after excavation under vertical load are studied by the simplified method. Computational results show that after excavation, the ultimate bearing capacity of pile and pile head stiffness will reduce. A rational prediction method for estimating the loss of bearing capacity should consider not only the decease of the overburden pressure of the surrounding soil, but also the increase of the K₀ coefficient and undrained shear strength.
- model test /
- excavation /
- ultimate bearing capacity /
- undrained shear strength /
- over-consolidation ratio

HTML全文

参考文献(15)

[1]	MOCHTAR I B, EDIL T B. Shaft resistance of model pile in clay[J]. Journal of Geotechnical Engineering, ASCE, 1988, 114(11): 1227-1243.
[2]	POULOS H G, CHAN K E. Laboratory study of pile skin friction in calcareous sand[R]. Sydney: University of Sydney, 1984.
[3]	IWASAKI Y, WATANABE H, FUKUDA M, et al. Construction control for underpinning piles and their behavior during excavation[J]. Géotechnique, 1994, 44(4): 681-689.
[4]	郦建俊, 黄茂松, 王卫东, 等. 开挖条件下抗拔桩承载力的离心模型试验[J]. 岩土工程学报, 2010, 32(3): 388-396. (LI Jian-jun, HUANG Mao-song, WANG Wei-dong, et al. Centrifugal model tests on bearing capacity of uplift piles under deep excavation[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(3): 388-396. (in Chinese))
[5]	刁钰. 超深开挖对坑底抗压桩竖向承载力及沉降特性影响研究[D]. 天津: 天津大学, 2011. (DIAO Yu. Studies on effects of super-deep excavation on the bearing capacity and settlement behavior of compression piles beneath the basement[D]. Tianjin: Tianjin University, 2011. (in Chinese))
[6]	陈锦剑, 吴琼, 王建华, 等. 开挖卸荷条件下单桩承载力特性的模型试验研究[J]. 岩土工程学报, 2010, 32(增刊2): 85-88. (CHEN Jin-jian, WU Qiong, WANG Jian-hua, et al. Model tests on bearing capacity of single pile influenced by excavation[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(S2): 85-88. (in Chinese))
[7]	罗耀武, 胡琦, 陈云敏, 等. 基坑开挖对抗拔桩极限承载力影响的模型试验研究[J]. 岩土工程学报, 2011, 33(3): 427-432. (LUO Yao-wu, HU Qi, CHEN Yun-min, et al. Model tests on ultimate uplift capacity of piles under excavation[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(3): 427-432. (in Chinese))
[8]	TOMLINSON M J. The adhesion of piles driven in clay soils[C]// Proceedings of the 4th International Conference on Soils Mechanics and Foundation Engineering, Vol 2. London: Thomas Telford Ltd, 1957: 66-71.
[9]	SLADEN J A. The adhesion factor: applications and limitations[J]. Canadian Geotechnical Journal, 1992, 29(2): 322-326.
[10]	CHERUBINI C. A few comments on pile design: discussion[J]. Canadian Geotechnical Journal, 1998, 35(5): 905.
[11]	LACASSE S, BOISARD P. Consequence of the new API RP2A guideline for piles in soft clays[C]// Proceedings of the 13th International Conference on Soil Mechanics and Foundation Engineering. New Delhi, 1994: 527-530.
[12]	American Petroleum Institute (API). Recommended practice for planning, designing and constructing fixed offshore platforms—load and resistance factor design[S]. 1993.
[13]	KOLK H J, van der VELDE E. A reliable method to determine the friction capacity of piles driven into clays[C]// Proceedings of the 28th Annual Offshore Technology Conference. Houston, 1996: 337-346.
[14]	纠永志. 开挖条件下软黏土地基桩筏基础非线性分析[D]. 上海: 同济大学, 2014. (JIU Yong-zhi. Nonlinear analysis of pile-raft foundations during excavation in soft clay[D]. Shanghai: Tongji University, 2014. (in Chinese))
[15]	KRAFT L M, RAY R P, KAGAWA T. Theoretical t - z curves[J]. Journal of the Geotechnical Engineering Division, ASCE, 1981, 107(11): 1543-1561.

施引文献(2)

期刊类型引用(2)

1.	许成顺，韩润波，杜修力，许紫刚. 考虑土-结构相互作用的弹簧-地下结构体系静力推覆试验技术及其试验研究. 建筑结构学报. 2023(01): 248-258 . 百度学术
2.	卢钦武，关振长，林林，吴淑婧，宋德杰. 基于静力推覆试验的山岭隧道衬砌-地层相互作用机制研究. 岩土力学. 2023(08): 2318-2326 . 百度学术