土–水特征曲线对非饱和砂土抗剪强度的影响

翟钱; 戴国亮; 赵学亮

doi:10.11779/CJGE202007018

土–水特征曲线对非饱和砂土抗剪强度的影响 English Version

翟钱^{1, 2,},
戴国亮^{1, 2},
赵学亮^{1, 2}

1.
东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏　南京　210096
2.
东南大学土木工程学院,江苏　南京　210096

基金项目:

中国华能集团有限公司科技项目 HNKJ19-H17

国家电网鲁能集团有限公司科技项目 SGDC0000KXJS1900137

国家自然科学基金项目 51878160

详细信息

作者简介:
翟钱(1982—),男,博士,副教授,主要从事非饱和土力学等方面的教学和科研工作。E-mail：101012332@seu.edu.cn

中图分类号: TU42;P66
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出版历程
- 收稿日期: 2019-07-24
- 网络出版日期: 2022-12-05
- 刊出日期: 2020-06-30

Effect of soil-water characteristic curve on shear strength of unsaturated sandy soils

ZHAI Qian^{1, 2,},
DAI Guo-liang^{1, 2},
ZHAO Xue-liang^{1, 2}

1.
Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education, Southeast University, Nanjing 210096, China
2.
School of Civil Engineering, Southeast University, Nanjing 210096, China

摘要

摘要: 因非饱和土的剪切试验设备成本比较高,通过间接手段估测非饱和土抗剪强度的方法日受欢迎,其中通过土–水特征曲线进行估测的方法最为普遍。通过修正传统毛细模型,结合概率统计学理论,为通过土–水特征曲线估测非饱和土抗剪强度的计算方法提供理论依据,并提出相关数学表达式。对比公式的估算值和现有文献的试验数据,发现估算值和试验数据基本吻合。此外,还发现很多文献中土–水特征曲线试验土样和非饱和土剪切试验土样并不在同一应力状态,如果忽略这样的应力状态差异,会增大估测的误差。因此,建议对传统张力仪或压力板试验的土–水特征曲线进行相关修正后再用以估测非饱和土抗剪强度。
- 孔径分布 /
- 非饱和土抗剪强度 /
- 修正毛细模型 /
- 土–水特征曲线 /
- 统计模型
Abstract: The experimental measurements of the shear strength of unsaturated soils are uncommonly emloyed in the practical engineering because the unsaturated experimental measurements are time-consuming and costly. Instead, the shear strength of unsaturated soils is commonly estimated from the soil-water characteristic curve (SWCC). In this study, an improved capillary model and a new mathematical equation are proposed for the estimation of the shear strength of unsaturated soils from the SWCC. The proposed equation is verified by the experimental data from the published literatures. It is observed that the soil specimen prepared for the SWCC tests may not be in the same stress state as that prepared for the shearing tests. In other words, the measured SWCC from the conventional Tempe cell and pressure plate may not agree with that of the specimen in the shearing tests. As a result, errors may be introduced in the estimated results of the shear strength of unsaturated soils. Consequently, the SWCCs obtained from the conventional method should be corrected for the estimation of the shear strength of the unsaturated soils with a high confining pressure.
- pore-size distribution /
- shear strength of unsaturated soils /
- improved capillary model /
- soil-water characteristic curve /
- statistical model

HTML全文

图 1 传统毛细模型^[31]

Figure 1. Conventional capillary model^[31]

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图 2 水分在孔隙中的迁移过程

Figure 2. Movement of water in pores

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图 3 不规则孔隙简化为系列不同尺寸的毛细管

Figure 3. Simplification of irregular pores into a series of capillary tubes with different radii

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图 4 土体单元孔隙的简化

Figure 4. Simplification of soil element

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图 5 孔径分布函数和土水特征曲线的关系

Figure 5. Illustration of pore-size distribution function and soil-water characteristic curve

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图 6 土颗粒间的弯液面

Figure 6. Illustration of meniscus between two soil particles

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图 7 弯液面简化分析模型

Figure 7. Simplified model for meniscus

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图 8 土体在不同吸力状态下因弯液面造成对土颗粒框架的压缩应力^[11]

Figure 8. Illustration of compression on soil skeleton due to meniscus under different suction levels^[11]

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图 9 土颗粒周围不同状态的水^[32]

Figure 9. Illustration of different types of water around soil particles^[32]

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图 10 团聚体间孔隙和团聚体内孔隙^[33]

Figure 10. Illustration of inter-aggregate and intra-aggregate pores

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图 11 修正后的土–水特征曲线

Figure 11. Illustration of modified soil-water characteristic curve

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图 12 压实高岭土、风化花岗岩和印度Head Till的土–水特征曲线

Figure 12. Experimental data of soil-water characteristic curve for compacted kaolin, weathered granite and Indian Head Till

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图 13 压实高岭土、风化花岗岩和印度Head Till的抗剪强度试验数据

Figure 13. Experimental data of shear strength of unsaturated compacted kaolin, weathered granite, and Indian Head Till

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图 14 压实高岭土、风化花岗岩和印度Head Till估测抗剪强度和试验数据的比较

Figure 14. Comparison between estimated results and measured data of shear strength for unsaturated compacted kaolin, weathered granite, and Indian Head Till

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图 15 选用单一土–水特征曲线估测风化花岗岩和印度Head Till估测抗剪强度和试验数据的比较

Figure 15. Comparison between estimated results using single SWCC and measured data of shear strength for unsaturated weathered granite and Indian Head Till

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表 1 压实高岭土、风化花岗岩和印度Head Till土水特性曲线的拟合参数

Table 1 The SWCC fitting parameters for compacted kaolin, weathered granite and Indian Head Till

土样	围压/kPa	F-X模型^[21]参数
土样	围压/kPa	a/kPa	n	m	C_r
压缩高岭土	100	83.40	3.76	0.74	1500
压缩高岭土	200	95.00	3.80	0.70	1500
压缩高岭土	300	101.00	3.80	0.65	1500
风化花岗岩	0	3.26	4.12	0.41	1500
风化花岗岩	100	7.67	2.60	0.53	1500
风化花岗岩	200	14.72	2.07	0.61	1500
风化花岗岩	300	23.85	1.89	0.65	1500
印度Head Till	预压25	34.10	0.80	0.57	3000
印度Head Till	预压100	71.40	0.66	0.54	3000
印度Head Till	预压200	125.20	0.81	0.45	3000

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