大直径超长钻孔灌注桩承载性状

冯忠居; 谢永利; 李哲; 张宏光

大直径超长钻孔灌注桩承载性状

长安大学特殊地区公路工程教育部重点实验室, 陕西西安 710064

基金项目:

国家西部交通建设科技项目 2001 318 000 17

详细信息

作者简介:
冯忠居(1965-), 男, 山西万荣人, 长安大学副教授, 博士, 从事岩土工程研究

中图分类号: U443.15
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- 被引次数: 0
出版历程
- 收稿日期: 2004-12-05
- 刊出日期: 2005-03-25

Bearing property of large-diameter over-length nonplacement pile

Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang'an University, Xi'an 710064, China

More Information

Author Bio:
FENG Zhong-ju(1965-), male, PhD, associate professor, 86-29-82336860, zhongjufeng@tom.com

摘要

摘要: 基于芝川河特大桥的桩基原位试验, 对粉质砂土地区大直径超长钻孔灌注桩的承载力性状进行了分析, 并将实测成果与现行《公路桥涵地基与基础设计规范》中经验公式的计算结果进行了对比分析。发现大直径超长钻孔灌注桩的承载力性状和中长桩或短桩的承载力性状具有明显差异; 粉质砂土处于地面以下的不同部位, 其侧阻力有较大差异; 规范公式计算承载力结果明显小于原位试验结果, 相差超过50%。研究结果表明, 相同土质处于地面以下不同部位对桩产生的极限摩阻力不同, 规范公式不适于评价大直径超长桩的承载力。
- 桥梁工程 /
- 大直径超长桩 /
- 承载力 /
- 粉质砂土 /
- 极限侧阻力 /
- 极限端阻力
Abstract: Based on the field test of pile foundation in Zhichuan river bridge, the bearing property of large-diameter over-length nonplacement pile in the area of powder sandy soil was studied, a comparison was made between the test result and the calculation value of empirical formula. It is pointed that there is a remarkable difference between the bearing property of large-diameter over-length nonplacement pile and that of medium length or short ones, when powder sandy soil is in different depth underground, its lateral resistance is different significantly, the bearing capacity difference of experimental piles and normalized formula is over 50%. The results show that the limiting lateral resistances of powder sandy soil of different depth are different, the normalized formula is not suited to evaluate the bearing capacity of large-diameter over-length nonplacement pile.
- bridge engineering /
- large-diameter over-length pile /
- bearing capacity /
- silty sand /
- limiting lateral resistance /
- limiting end resistance

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图 1 荷载(Q) 与沉降(S) 分布曲线

Figure 1. Load-settlement curves

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图 2 桩的轴力分布

Figure 2. Arrangement curves of axial force

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图 3 桩端阻力分布曲线

Figure 3. Arrangement curve of pile end resistance

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图 4 桩侧阻力分布曲线

Figure 4. Arrangement curves of side resistance

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表 1 各级荷载下桩端阻力

Table 1. Pile end resistance under different loads

	荷载等级/MN
	1.6、3.2、4.8、8.0、9.6	11.2	12.8	14.4	16.0	17.6	19.2
桩端荷载/MN	0	0.44	0.88	1.14	1.28	1.62	1.75
端阻占各级荷载百分比/%	0	3.7	6.9	7.9	8.0	9.2	9.1

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表 2 桩侧土层极限侧摩阻力

Table 2. Limiting lateral resistance of side pile soil layers

土层	土名	测试极限摩阻力/kPa	规范值/kPa
1	细砂	90.82	20~80
2	中砂	53.20	55~90
3	卵石	77.09	—
4	细砂	27.44	20~80
5	粉质粘土	49.06	15~95
6	细砂	84.31	20~80
7	粉质粘土	27.55	15~95
8	细砂	83.06	20~80

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表 3 各土层参数取值

Table 3. Parameters of different soil layers

承载力	土名
承载力	细砂	中砂	卵石	粉质粘土
[σ]/kPa	80	300	600	280
[τ]/kPa	30	40	150	40
λ=0.85 m₀=0.90

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参考文献(9)

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