Centrifugal model tests on vertical bearing characteristics of undercompacted slope piles
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摘要: 现有的桩基理论与经验基本上是基于平坡条件下建立的，而工程中常见的欠压实斜坡桩的受力特性与平坡桩基存在着较大差异。基于斜坡桩的受力特点，开展了3组离心模型试验，研究了欠压实斜坡基桩在竖向荷载作用下的承载特性，获得了桩侧摩阻力、桩身轴力、桩体竖向位移的分布特征以及桩周土体的沉降规律，分析了边坡填筑压实度、坡比等因素对桩土非协调变形的影响。主要研究成果为：①欠压实斜坡基桩桩体受力主要包括桩侧正摩阻力、桩侧负摩阻力、桩端端阻力及边坡土体对桩体产生的下滑力等4部分。②桩周土体压实度对桩侧摩阻力沿深度分布及桩端阻力影响较大；斜坡坡度对桩侧摩阻力沿同截面桩身分布及侧阻力的峰值影响较大。③斜坡桩负摩阻力中性点约在0.5~0.6倍桩长埋深处，若按常规的承载桩基进行设计，桩体额外承受的负摩阻力和侧向荷载容易引起桩体破坏。Abstract: The existing theories and experience of pile foundation are based on the flat slopes, and the stress characteristics of undercompacted slope piles are quite different from those of flat slope piles. Based on the stress characteristics of slope piles, three groups of centrifugal model tests are carried out to study the bearing characteristics of foundation piles under vertical loads. The distribution characteristics of side friction resistance, axial force, vertical displacement of piles and the settlement laws of soils around the piles are obtained. The influences of compaction degree and slope ratio on the uncoordinated deformations of the piles and soils are analyzed. The results are as follows: (1) The stress of the undercompacted slope piles includes the positive friction resistance at the pile side, the negative friction resistance at the pile side, the resistance at the pile end and the sliding force of the slope. (2) The compaction degree of soils has a great influence on the distribution of pile side friction along the depth and pile tip resistance. The slope gradient has a great influence on the distribution of pile side friction resistance and the peak value of side resistance. (3) The neutral point of the negative friction resistance of the slope pile is about 0.5 ~ 0.6 times the length of the pile along the burial depth. According to the conventional design, the additional negative friction resistance and lateral load of the piles are easy to cause pile damage.
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Keywords:
- undercompaction /
- slope /
- centrifugal model test /
- bearing characteristic
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图 7 SY1桩身轴力和摩阻力分布图
Figure 7. Distribution of axial force and friction resistance of pile SY1
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图 8 SY2桩身轴力和摩阻力分布图
Figure 8. Distribution of axial force and friction resistance of pile SY2
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图 9 SY3桩身轴力和摩阻力分布图
Figure 9. Distribution of axial force and friction resistance of pile SY3
表 1 离心模型试验组合工况表
Table 1 Working conditions for centrifugal tests
编号 填方高度/cm 填筑体压实度/% 坡比 桩顶荷载 SY1 30 80 平坡 无荷载 SY2 30 95 1∶2 竖向荷载 SY3 30 80 1∶2 竖向荷载 
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[1] 龚晓南. 桩基工程手册[M]. 2版. 北京: 中国建筑工业出版社, 2016. GONG Xiaonan. Handbook of Pile Foundation Engineering[M]. 2nd ed. Beijing: China Architecture & Building Press, 2016. (in Chinese)
[2] 程刘勇, 陈善雄, 余飞, 等. 竖向荷载下斜坡桩基承载力及影响因素数值研究[J]. 科学技术与工程, 2013, 13(18): 5399-5403, 5422. doi: 10.3969/j.issn.1671-1815.2013.18.060 CHENG Liuyong, CHEN Shanxiong, YU Fei, et al. Numerical simulation for vertical ultimate capacity and influencing factors of oblique slope pile under vertical loads[J]. Science Technology and Engineering, 2013, 13(18): 5399-5403, 5422. (in Chinese) doi: 10.3969/j.issn.1671-1815.2013.18.060
[3] 胡明源, 张建伟, 王宏权, 等. 复杂荷载下斜坡上单桩水平承载特性研究[J]. 河南大学学报(自然科学版), 2017, 47(5): 584-590. HU Mingyuan, ZHANG Jianwei, WANG Hongquan, et al. Study on the bearing characteristics of pile on slope under complex loads[J]. Journal of Henan University (Natural Science), 2017, 47(5): 584-590. (in Chinese)
[4] JIANG C, LI T B, ZHOU K P, et al. Reliability analysis of piles constructed on slopes under laterally loading[J]. Transactions of Nonferrous Metals Society of China, 2016, 26(7): 1955-1964. doi: 10.1016/S1003-6326(16)64306-6
[5] 彭文哲, 赵明华, 杨超炜, 等. 斜坡地基桩前土抗力的应变楔模型修正[J]. 中南大学学报(自然科学版)2020, 51(7): 1936-1945. PENG Wenzhe, ZHAO Minghua, YANG Chaowei, et al. Modification of strain wedge model for soil resistance in front of piles in sloping ground[J]. Journal of Central South University(Science and Technology), 2020, 51(7): 1936-1945. (in Chinese)
[6] 尹平保, 赵明华, 赵衡, 等. 考虑斜坡效应的桩柱式桥梁基桩稳定性分析[J]. 湖南大学学报(自然科学版), 2016, 43(11): 20-25. doi: 10.3969/j.issn.1674-2974.2016.11.004 YIN Pingbao, ZHAO Minghua, ZHAO Heng, et al. Stability analysis of pile-column bridge pile considering slope effect[J]. Journal of Hunan University (Natural Sciences), 2016, 43(11): 20-25. (in Chinese) doi: 10.3969/j.issn.1674-2974.2016.11.004
[7] 文松霖, 胡胜刚, 胡汉兵, 等. 渠坡上基桩的水平承载机制试验研究[J]. 岩土力学, 2010, 31(6): 1786-1790. doi: 10.3969/j.issn.1000-7598.2010.06.018 WEN Songlin, HU Shenggang, HU Hanbing, et al. Test sduty of horizontal bearing mechanism of pile on canal slope[J]. Rock and Soil Mechanics, 2010, 31(6): 1786-1790. (in Chinese) doi: 10.3969/j.issn.1000-7598.2010.06.018
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