黄土地基中人工挖孔扩底灌注桩负摩阻力试验研究

摘要
图/表
参考文献(14)
相关文章 (15)

全文: PDF (1572 KB) HTML (1 KB)
输出: BibTeX | EndNote (RIS)

摘要通过2根试桩的现场预浸水再加载试验，研究湿陷性黄土地基中人工挖孔扩底灌注桩在预浸水过程及其之后的加载过程中桩身摩阻力、桩端反力及桩身中性点深度的发展变化规律，并与我国现行规范进行比较。结果表明：(1) 桩周土浸水过程中，桩身负摩阻力、正摩阻力及桩端反力均逐渐增大，桩身中性点位置逐渐下移。浸水结束时，中性点深度比为0.54～0.61，远小于桩基规范的推荐值；(2) 在桩顶施加竖向荷载过程中，桩身负摩阻力逐渐减小，而正摩阻力及桩端反力继续增大，桩身中性点位置逐渐上移。桩顶竖向荷载P = 11 000 kN时，中性点深度比为0.15～0.61，也远小于桩基规范的推荐值；(3) 在桩顶设计荷载作用下，实测的桩身负摩阻力大小、分布范围及分布形式与桩基规范及黄土规范的规定有较大的差异；(4) 黄土地基中桩身负摩阻力及中性点深度随着桩周土浸水、桩顶荷载处于一个动态变化过程中，负摩阻力的大小也受到桩径的影响。

	服务

	把本文推荐给朋友
	加入我的书架
	加入引用管理器
	E-mail Alert
	RSS
	作者相关文章
	曹卫平1
	赵敏2

关键词 ：桩基础, 黄土, 人工挖孔扩底灌注桩, 试验研究, 负摩阻力, 中性点

Abstract：Field tests were conducted to investigate the behavior of negative skin friction，positive skin friction，pile end reaction and neutral plane depth for man-made cast-in-situ belled piles in loess under pre-immersing and loading condition. The test results were also compared with the regulations of the technical code for building pile foundation of China. The results show that：(1) With the pre-immersing，negative skin friction，positive skin friction and pile end reaction are induced and increase with further immersing and the neutral plane gradually descend. The neutral plane depth ratio reaches 0.54–0.61 at the end of pre-immersing process，which is far smaller than that introduced in the technical code for building pile foundation of China. (2) When vertical load is applied on the pile head，negative skin friction decrease accompanied by the increasing of positive skin friction and pile end reaction as well as the ascending of the neutral plane. The neutral plane depth ratio reaches about 0.15–0.61 when P = 11 000 kN，which is also far smaller than that introduced in the technical code for building pile foundation of China. (3) The measured negative skin friction and its distribution dramatically differ from the ones calculated according to the technical code for building pile foundation of China. (4) The negative skin friction and the neutral plane depth are in a dynamic process with the immersing and the loading as well as the pile shaft diameter.

Key words： pile foundations loess soil man-made cast-in-situ belled pile experimental study negative skin friction neutral plane

引用本文:

曹卫平1，赵敏2. 黄土地基中人工挖孔扩底灌注桩负摩阻力试验研究[J]. 岩石力学与工程学报, 2012, 31(S1): 3167-3173.
CAO Weiping1，ZHAO Min2. EXPERIMENTAL STUDY OF NEGATIVE SKIN FRICTION FOR MAN-MADE CAST-IN-SITU BELLED PILES IN LOESS SOIL FOUNDATION. , 2012, 31(S1): 3167-3173.

链接本文:

https://rockmech.whrsm.ac.cn/CN/Y2012/V31/IS1/3167

[1] 李大展，腾延京，何颐华. 湿陷性黄土中大直径扩底桩垂直承载性状的试验研究[J]. 岩土工程学报，1994，16(2)：11–21.(LI Dazhan，TENG Yanjing，HE Yihua. Vertical bearing behavior of large diameter belled pile in collapsed loess[J]. Chinese Journal of Geotechnical Engineering，1994，16(2)：11–21.(in Chinese))

[2] 黄学峰，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.(HUANG Xuefeng，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))

[3] 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. (FENG Shijin，KE Han，CHEN Yunmin，et al. Experimental study on super-long bored pile in loess[J]. Chinese Journal of Geotechnical Engineering，2004，26(1)：110–114.(in Chinese))

[4] 冯忠居，谢永利，张宏光，等. 地面水对黄土地区桥梁桩基承载力影响试验研究[J]. 岩石力学与工程学报，2005，24(10)：1 758– 1 765.(FENG Zhongju，XIE Yongli，ZHANG Hongguang，et al. Experimental study on effect of surface water on bearing capacity of pile foundation in loess area[J]. Chinese Journal of Rock Mechanics and Engineering，2005，24(10)：1 758–1 765.(in Chinese))

[5] 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.(LIU Mingzhen. 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))

[6] 中华人民共和国行业标准编写组. JGJ94－2008建筑桩基技术规范[S]. 北京：中国建筑工业出版社，2008.(The Professional Standards Compilation Group of People¢s Republic of China. JGJ94－2008 Technical code for building pile foundations[S]. Beijing：China Architecture and Building Press，2008.(in Chinese))

[7] 中华人民共和国国家标准编写组. GB50025－2004湿陷性黄土地区建筑规范[S]. 北京：中国建筑工业出版社，2004.(The National Standards Compilation Group of People¢s Republic of China. GB50025－2004 Technical code for building in loess soil[S]. Beijing：China Architecture and Building Press，2004.(in Chinese))

[8] Fellenius B H. Results from long-term measurement in piles of drag load and downdrag[J]. Canadian Geotechnical Journal，2006，43(4)：409–430.

[9] Yin Z Z，Zhu H，Xu G H. A study of deformation in interface between soil and concrete[J]. Computers and Geotechnics，1995，17(1)：75–92.

[10] Gómez J E，Filz G M，Ebeling R M. Development of an improved numerical model for concrete-to-soil interfaces in soil-structure interaction analyses[R]. Vicksburg，Miss：Army Engineer Research and Development Center，2000.

[11] 曹卫平. 桩土界面荷载传递双曲线模型的改进及其应用[J]. 岩石力学与工程学报，2009，28(1)：144–151.(CAO Weiping. An improved load transfer hyperbolic model for pile-soil interface and its application[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(1)：144–151.(in Chinese))

[12] CHEN R P，ZHOU W H，CHEN Y M. Influences of soil consolidation and pile load on the development of negative skin friction of a pile[J]. Computers and Geotechnics，2009，36(8)：1 265– 1 271.

[13] 马时冬. 桩身负摩阻力的现场测试与研究[J]. 岩土力学，1997，18(1)：8–15.(MA Shidong. Study on the field measurement of negative friction of piles[J]. Rock and Soil Mechanics，1997，18(1)：8–15.(in Chinese))

[14] 夏力农，王星华，蒋春平. 桩顶荷载对桩基负摩阻力特性的影响[J].防灾减灾工程学报，2005，25(4)：359–362.(XIA Linong，WANG Xinghua，JIANG Chunping. Influence of working load on negative skin friction characters of pile[J]. Journal of Disaster Prevention and Mitigation Engineering，2005，25(4)：359–362.(in Chinese))