硬壳层对管桩复合地基桩-土应力比的影响

陈永辉; 韩丹丹; 孔纲强; 陈龙; 陈庚

doi:10.3969/j.issn.0258-2724.20210612

硬壳层对管桩复合地基桩-土应力比的影响

doi: 10.3969/j.issn.0258-2724.20210612

河海大学岩土力学与堤坝工程教育部重点实验室，江苏南京 210098

基金项目: 浙江省交通运输厅科技计划项目（2020029）；中央高校基本科研业务费项目(B200201049）

详细信息

作者简介:
陈永辉（1972—），男，教授，长江学者，博士，研究方向为软土工程安全及资源化利用，E-mail：yonghuich@163.com

通讯作者:
孔纲强（1982—），男，教授，博士，研究方向为能源岩土工程，E-mail：gqkong1@163.com

中图分类号: TU447
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- 被引次数: 0
出版历程
- 收稿日期: 2021-07-26
- 修回日期: 2022-03-01
- 网络出版日期: 2023-06-28
- 刊出日期: 2022-04-11

Effect of Artificial Crust Layer on Pile-Soil Stress Ratio of Pipe Pile Composite Foundation

Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, China

摘要

摘要:
为研究就地固化硬壳层对预应力管桩复合地基桩-土应力比的影响，以绍兴钱滨线泥浆池路段为背景，开展现场试验和数值模拟分析，研究路堤荷载作用下预应力管桩复合地基的受力和变形；从桩-土应力比的角度，着重探讨硬壳层对桩基复合地基承载性能的影响规律；分析路堤高度与桩帽净间距之比、桩帽宽度与桩帽净间距之比等设计参数对桩-土应力比发展的影响机制. 研究结果表明：硬壳层的存在能够有效提高桩基复合地基的承载特性；在本文试验条件下，就地固化硬壳层的预应力管桩复合地基最大水平位移发生在地表以下5～6 m处，区别于传统桩基复合地基的土体水平位移沿深度逐渐降低的规律；桩-土应力比在23～37，高于传统桩基复合地基.
- 道路工程 /
- 就地固化 /
- 预应力管桩 /
- 桩-土应力比 /
- 现场试验
Abstract:
In order to study the influence of artificial crust layer formed by in-situ solidified on the pile-soil stress ratio of prestressed pipe pile composite foundation, field experiments and numerical simulation analysis were carried out based on the mud pit section of Qianqing-Binhai highway in Shaoxing. On this basis, both the stress response and deformation of prestressed pipe pile composite foundation under embankment load were studied. From the pile-soil stress ratio, the influence of artificial crust layer on the bearing performance of pile composite foundation was emphatically discussed. In addition, the influence mechanism of design parameters such as the ratio of embankment height to net distance between pile caps and the ratio of pile cap width to net distance between pile caps on the development of pile-soil stress ratio were preliminarily studied. It shows that artificial crust layer can improve the bearing capacity. Under the experimental conditions, the maximum horizontal displacement of artificial crust layer combined prestressed pipe pile composite foundation occurs 5～6 m below the ground surface, which is different from traditional composite foundation decreases gradually along the depth. The pile-soil stress ratio is between 23 and 37, which is higher than that of traditional pile composite foundation.
- road engineering /
- in-situ solidification /
- prestressed pipe pile /
- pile-soil stress ratio /
- field experiment

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图 1 就地固化结合预应力管桩的复合地基示意（单位：m）

Figure 1. Schematic of composite foundation of in-situ solidification combined with prestressed pipe pile （unit: m）

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图 2 有限元网格和边界条件（单位：m）

Figure 2. Finite element mesh and boundary conditions （unit: m）

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图 3 孔隙水压力的数值模拟结果

Figure 3. Numerical simulation results of pore water pressure

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图 4 路堤竖向沉降的数值模拟结果

Figure 4. Numerical simulation results of vertical settlement

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图 5 地基沉降随深度变化规律曲线

Figure 5. Curves of settlement of layer soil along depth

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图 6 水平位移随深度变化规律曲线

Figure 6. Curves of horizontal displacement along depth

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图 7 应力时程曲线图

Figure 7. Time-history curves of stress

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图 8 桩-土应力比变化规律对比曲线

Figure 8. Comparison of variation law of pile-soil stress ratio

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图 9 h/s与桩-土应力比变化规律

Figure 9. Variation of h/s versus pile-soil stress ratio

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图 10 b/s与桩-土应力比变化规律

Figure 10. Variation of b/s versus pile-soil stress ratio

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表 1 试验段土层的基本物理力学指标

Table 1. Basic physical and mechanical indexes of soil layer

土层	厚度/m	天然湿密度/ （g•cm⁻³）	天然孔隙比	黏聚力/kPa	内摩擦角/（°）	弹性模量/ MPa	泊松比	渗透率/ （×10⁻⁴ m•d⁻¹）
路堤	4.5			2.0	38.0	35.00	0.30	1000.0
土工格栅						3500.00	0.30
桩						80000.00	0.15
硬壳层	3.0	1.85	0.380	300.0	16.0	300.00	0.30	1.0
泥浆	9.0	1.69	2.060	10.0	10.1	2.50	0.35	1.7
粉土	1.0	1.79	0.902	8.2	29.2	4.46	0.35	4.3
粉砂	7.0	1.79	0.735	6.4	30.9	6.32	0.35	43.2
淤泥质黏土	19.0	1.78	1.212	15.0	3.7	2.73	0.35	4.3

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表 2 施工参数对比表

Table 2. Comparison of construction parameters

工况	来源	桩长/m	桩径/m	桩间距/m	桩间土应力/kPa	桩顶土应力/kPa	桩-土应力比	褥垫层/硬壳层
1	本文	16.0	0.40	2.5	88.3	2785.8	31.6	3.0 m 硬壳层
2	文献[6]	16.0	0.40	2.5	90.8	2851.1	31.4	3.0 m 硬壳层
3	文献[7]	16.0	0.40	3.0	97.0	3073.8	31.7	3.0 m 硬壳层
4	文献[12]	20.0	0.40	2.0	18.2	375.0	20.6	加筋垫层（土工格栅抗拉模量1000 kN/m，垫层和整平层压缩模量 25 MPa）
5				2.5	46.6	289.9	6.2
6				3.0	24.3	381.1	15.7
7	文献[12]	14.0	0.40	2.0	24.1	281.0	11.7	加筋垫层（土工格栅抗拉模量 600 kN/m，垫层和整平层压缩模量 25 MPa）
8	文献[12]	14.0	0.30	2.5	40.1	292.2	7.3
9	文献[12]	13.5	0.48	2.7	30.4	350.8	11.5
10	文献[12]	13.5	0.48	2.2	20.9	269.3	12.9
11	文献[13]	7.0～8.0	0.50	1.2			3.8	0.5 m 砂性土
12	文献[13]	7.0～8.0	0.50	1.2			5.0	0.5 m 碎石垫层
13	文献[14]	16.0	1.00	3.0	58.9	624.9	8.9	0.5 m 碎石垫层+土工格栅（抗拉模量 1180 kN/m）
14	文献[20]	3.0～6.0	0.50	1.6	115.1	177.3	1.5	0.5 m 碎石垫层+土工格栅（抗拉模量 300 kN/m）

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表 3 参数影响程度

Table 3. Influence degree of parameters

影响因素	影响程度/%	结论
h/s	108.6	高（+）
b/s	63.0	高（+）
注：表中“ + ”表示积极影响.

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