Model tests on bearing behavior of pile groups in collapsible loess ground under water immersion

ZHANG Yan-jie; WANG Xu; LIANG Qing-guo; JIANG Dai-jun; LI Jian-dong

doi:10.11779/CJGE2021S1040

Volume 43 Issue S1

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Chinese Journal of Geotechnical Engineering > 2021 > 43(S1): 219-223. > DOI: 10.11779/CJGE2021S1040

ZHANG Yan-jie, WANG Xu, LIANG Qing-guo, JIANG Dai-jun, LI Jian-dong. Model tests on bearing behavior of pile groups in collapsible loess ground under water immersion[J]. Chinese Journal of Geotechnical Engineering, 2021, 43(S1): 219-223. DOI: 10.11779/CJGE2021S1040

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Model tests on bearing behavior of pile groups in collapsible loess ground under water immersion

1.
School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
2.
Key Laboratory of Road&Bridge and Underground Engineering of Gansu Province, Lanzhou 730070, China

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Received Date: December 14, 2020
Available Online: December 05, 2022

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Abstract

Abstract

The artificially prepared collapsible loess is used as the similar material to carry out 2×2 pile group model tests under water immersion.The change law of collapsibility deformation and the load transfer mechanism are analyzed.The results show that with the increase of soaking time, the relationship between the cumulative collapse settlement and the time mainly includes the initial gentle section, immersion steep drop section, medium gentle section and gentle section after water cut.With the increase of collapse depth, the negative frictional resistance develops from top to bottom, and the depth of neutral point moves down gradually.When the settlement achieves stability, the neutral point depth ratio is 0.7.In large-thickness collapsible loess, when the depth of collapsible loess is determined by the laboratory experiments, and considering the working load on pile top, the neutral depth ratio of negative friction resistance can be determined by the recommended value of technical specification for building pile foundation.In the steep drop period of water immersion for collapsible deformation of soil layer, the negative friction resistance acting on the pile increases rapidly, which leads to the increase of downward load and pile end load and gradual increase of the settlement of pile foundation.Collapse of soil layer presents a synchronous trend with the negative friction of pile side and the occurrence and development of pile foundation settlement.
- pile foundation engineering,
- collapsible loess,
- pile group,
- negative skin friction,
- model test

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References

[1]	冯世进, 柯瀚, 陈云敏, 等. 黄土地基中超长钻孔灌注桩承载性状试验研究[J]. 岩土工程学报, 2004, 26(1): 110-114. doi: 10.3321/j.issn:1000-4548.2004.01.021 FENG Shi-jin, KE Han, CHEN Yun-min, et al. Experimental study on super-long bored pile in loess[J]. Chinese Journal of Geotechnical Engineering, 2004, 26(1): 110-114. (in Chinese) doi: 10.3321/j.issn:1000-4548.2004.01.021
[2]	朱彦鹏, 杨校辉, 马天忠, 等. 黄土塬地区大直径长桩承载性状与优化设计研究[J]. 岩石力学与工程学报, 2017, 36(4): 1012-1023. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201704025.htm ZHU Yan-peng, YANG Xiao-hui, MA Tianzhong, et al. Bearing behavior and optimization design of large-diameter long pile foundation in loess subsoil[J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 36(4): 1012-1023. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201704025.htm
[3]	黄雪峰, 陈正汉, 哈双, 等. 大厚度自重湿陷性黄土中灌注桩承载性状与负摩阻力的试验研究[J]. 岩土工程学报, 2007, 29(3): 338-346. doi: 10.3321/j.issn:1000-4548.2007.03.005 HUANG Xue-feng, CHEN Zhenghan, HA Shuang, et al. Research on bearing behaviors and negative friction force for filling piles in the site of collapsible loess with big thickness[J]. Chinese Journal of Geotechnical Engineering, 2007, 29(3): 338-346. (in Chinese) doi: 10.3321/j.issn:1000-4548.2007.03.005
[4]	任鹏. 黄土地基超长基桩竖向承载特性研究[D]. 成都: 西南交通大学, 2009. REN Peng. Vertical Load Bearing Behaviors of Super-long Pile in LoessSubgrade[D]. Chengdu: SouthwestJiaotongUniversity, 2009. (in Chinese)
[5]	杨校辉, 黄雪峰, 朱彦鹏, 等. 大厚度自重湿陷性黄土地基处理深度和湿陷性评价试验研究[J]. 岩石力学与工程学报, 2014, 33(5): 1063-1074. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201405022.htm YANG Xiao-hui, HUANG Xue-feng, ZHU Yan-peng, et al. Experimental study on collapsibility evaluation and treatment depths of collapsible loess upon self-weight with thick depth[J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(5): 1063-1074. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201405022.htm
[6]	MASHHOUR I, HANNA A. Drag load on end-bearing piles incollapsiblesoilduetoinundation[J]. Canadian Geotechnical Journal, 2016, 53(12): 2030-2038. doi: 10.1139/cgj-2015-0548
[7]	HANNA A M, SHARIF A. Drag force on a single pile in clay subjected to surcharge loading[J]. International Journal of Geomechanics, ASCE, 2006, 6(2): 89-96. doi: 10.1061/(ASCE)1532-3641(2006)6:2(89)
[8]	高永贵. 黄土中低承台群桩承载性能的试验研究[J]. 西安冶金建筑学院学报, 1994, 26(4): 355-360. https://www.cnki.com.cn/Article/CJFDTOTAL-XAJZ404.004.htm GAO Yonggui. Experimental study on the load-capacity behavior of pile groups with low cap in loess[J]. Journal of Xi'an Inst.of Metall.&Cons.Eng, 1994, 26(4): 355-360. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-XAJZ404.004.htm
[9]	刘明振. 含有自重湿陷性黄土夹层的场地上群桩负摩擦力的计算[J]. 岩土工程学报, 1999, 21(6): 749-752. doi: 10.3321/j.issn:1000-4548.1999.06.025 LIU Min-zhen. A calculation method of negative skin friction on the pile group in the self-weight collapsible loess stratum[J]. Chinese Journal of Geotechnical Engineering, 1999, 21(6): 749-752. (in Chinese) doi: 10.3321/j.issn:1000-4548.1999.06.025
[10]	张延杰, 王旭, 梁庆国, 等. 湿陷性黄土模型试验相似材料的研制[J]. 岩石力学与工程学报, 2013, 32(增刊2): 4019-4024. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX2013S2127.htm ZHANG Yan-jie, WANG Xu, LIANG Qingguo, et al. Development of model test similar material of collapsible loess[J]. Chinese Journal of Geotechnical Engineering, 2013, 32(S2): 4019-4024. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX2013S2127.htm
[11]	建筑基桩检测技术规范：JGJ106—2014[S].
[12]	李建东, 王旭, 张延杰, 等. 大厚度黄土地基超长群桩承载特性模型试验研究[J]. 工程地质学报, 2018, 26(6): 1708-1714. https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201806034.htm LI Jian-dong, WANG Xu, ZHANG Yan-jie, et al. Model tests for bearing behavior of large diameter and super long pile group in large thickness loess site[J]. Journal of Engineering Geology, 2018, 26(6): 1708-1714. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201806034.htm
[13]	钱鸿缙, 王继堂, 罗玉生, 等. 湿陷性黄土地基[M]. 北京: 中国建筑工业出版社, 1985. QIAN Hong-jin, WANG Jitang, LUO Yu-sheng, et al. Collapsed Loess Foundation[M]. Beijing: China Architecture and Building Press, 1985. (in Chinese)
[14]	建筑桩基技术规范：JGJ 94—2008[S]. 2008.
[15]	黄雪峰, 杨校辉, 殷鹤, 等. 湿陷性黄土场地湿陷下限深度与桩基中性点位置关系研究[J]. 岩土力学, 2015, 36(增刊2): 296-302. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX2015S2040.htm HUANG Xue-feng, YANG Xiao-hui, YIN He, et al. Study of relationship between maximum collapsing depth and neutral point position of pile foundation in collapsible loess ground[J]. Rock and Soil Mechanics, 2015, 36(S2): 296-302. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX2015S2040.htm