考虑净正应力影响的膨胀土土-水特征曲线试验研究

王晓琪; 汪时机; 程明书; 李贤; 周超云; 何丙辉

doi:10.11779/CJGE2018S1038

考虑净正应力影响的膨胀土土-水特征曲线试验研究 English Version

王晓琪¹,
汪时机^1, ,,
程明书¹,
李贤^{1, 2},
周超云¹,
何丙辉²

1. 西南大学工程技术学院,重庆 400715;
2. 西南大学资源环境学院,重庆 400715

基金项目: 国家自然科学基金项目（11572262,41771312）; 中央高校基本业务费专项资金项目（XDJK2018AB003）

详细信息

作者简介:
王晓琪(1994- ),女,硕士研究生,主要从事岩土力学方面的研究。E-mail：xqwang1994@163.com。

通讯作者:
汪时机，E-mail：shijiwang@swu.edu.cn

中图分类号: TU43
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出版历程
- 收稿日期: 2017-06-10
- 发布日期: 2018-08-24

Experimental study on soil-water characteristic curve of expensive soil considering net normal stress

1. College of Engineering and Technology, Southwest University, Chongqing 400715, China;
2. College of Resource and Environment, Southwest University, Chongqing 400715, China

摘要

摘要: 工程建设中,具有胀缩性、裂隙性和超固结性等特殊性质的膨胀土多处于非饱和状态和复杂变化的外加应力环境下,对膨胀土进行考虑应力状态的土-水特征曲线（soil-water characteristic curve,SWCC）试验研究,定性描述和定量表征膨胀土在一定应力状态下的土水特征,具有工程实践意义。采用GEO-Experts高级型应力相关土-水特征曲线压力板仪（SDSWCC-H）测定了河南南阳膨胀土在4个不同净正应力下（0,40,99,199 kPa）的土-水特征曲线,并利用试验数据对提出的能明确考虑净正应力影响的膨胀土SWCC表征方程进行验证。结果表明：①由于土体的间断级配,南阳膨胀土呈现出双峰土-水特征曲线（bimodal soil-water characteristic curve）;②净正应力会对膨胀土的持水能力与进气值产生影响,具体表现为在10~100 kPa基质吸力范围内,净正应力会显著影响膨胀土在脱湿过程中水分排出的速度;净正应力也改变了双峰SWCC第二个波峰的进气值;③已提出的SWCC模型曲线拟合精度较高,拟合结果良好,模型可以很好地表征南阳膨胀土在恒定净正应力下基质吸力与持水量的关系。
- 膨胀土 /
- 土-水特征曲线 /
- 净正应力 /
- 持水特性 /
- 拟合
Abstract: The expansive soil is a kind of special soil with swell-shrinking, fractured and over-consolidated properties. In engineering construction, the expansive soil is generally under unsaturated state and complex applied stress environment. It is practical to describe qualitatively and quantitatively the soil-water characteristic curve (SWCC) of the expansive soil under a certain stress state. Based on this, the SWCC of Nanyang expansive soil in Henan Province are measured under four different net normal stresses (0, 40, 99, 199 kPa) using the GEO-Experts high-type pressure plate apparatus for stress-dependent SWCC (SDSWCC-H). Furthermore, a proposed SWCC equation which can clearly consider the effect of the net normal stress is validated using the experimental data. The results suggest that: (1) Nanyang expansive soil presents bimodal SWCCs because of gap-graded soil; (2) The net normal stress can significantly affect moisture realease speed of soil in the matrix suction range from 10 to 100 kPa and also change the air-entry vaule of expansive soil; (3) The accuracy of the SWCC model based on measured data of bimodal SWCC for Nanyang expansive soil is verified with high fitting precision. The proposed SWCC model can well reflect the relationship between matrix suction and water retention capacity under constant net normal stress.
- expensive soil /
- soil-water characteristic curve /
- net normal stress /
- water retention property /
- fitting

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参考文献(17)

[1]	郭利娜, 胡斌, 宋友建, 等. 土-水特征曲线预测非饱和土的抗剪强度对比研究[J]. 工程地质学报, 2013, 21(6): 849-856. (GUO Li-na, HU Bing, SONG You-jian, et al.Contrast study on forecast of shear strength of unsatuarted soil using soil water characteristic curve[J]. Journal of Engineering Geology, 2013, 21(6): 849-856. (in Chinese ))
[2]	辛志宇, 谭晓慧, 王雪, 等. 膨胀土增湿过程中吸力-孔隙比-含水率关系[J]. 岩土工程学报, 2015, 37(7): 1195-1203. (XIN Zhi-yu, TAN Xiao-hui, WANG Xue, et al.Relationship among suction, void ratio and water content of expansive soils during wetting process[J]. Chinese Journal of Geotechnical Engineering, 2015, 37(7): 1195-1203. (in Chinese))
[3]	GENUCHTEN M T Van. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J]. Soil Science Society of America Journal, 1980, 44(44): 892-898.
[4]	FREDLUND D G, XING An-qing.Equations for the soil-water characteristic curve[J]. Canadian Geotechnical Journal, 1994, 31(4): 521-532.
[5]	GALLIPOLI D, WHEELER S J, KARSTUNEN M.Modelling the variation of degree of saturation in a deformable unsaturated soil[J]. Géotechnique, 2003, 53(53): 105-112.
[6]	GARDNER W R.Some steady-state solutions of the unsaturated moisture flow equation with application to evaporation from a water table[J]. Soil Science, 1958, 85(4): 228-232.
[7]	BROOKS R J, COREY A T.Hydraulic properties of porous medium[D]. Fort Collins: Colorado State University Hydrology, 1964, 3(1): 352-366.
[8]	程明书, 李贤, 汪时机, 等. 非饱和土双应力变量广义土水特征曲线模型验证[J]. 农业工程学报, 2016, 33(6): 8-17. (CHENG Ming-shu, LI Xian, WANG Shi-ji, et al.Model verification of generalized soil-water characteristic curve considering two stress state variables for unsaturated soils[J]. Transactions of the Chinese Society of Agricultural Engineering, 2016, 33(6): 8-17. (in Chinese))
[9]	VANAPALLI S K, FREDLUND D G, PUFAHL D E.The influence of soil structure and stress history on the soil-water characteristics of a compacted till[J]. Géotechnique, 1999, 49(2): 143-160.
[10]	NG C W W, PANG Y W. Experimental investigations of the soil-water characteristics of a volcanic soil[J]. Canadian Geotechnical Journal, 2000, 37(6): 1252-1264.
[11]	NG C W W, WONG H N, TSE Y M, et al. A field study of stress-dependent soil-water characteristic curves and permeability of a saprolitic slope in Hong Kong[J]. Géotechnique, 2011, 61(6): 511-521.
[12]	缪林昌, 刘松玉. 南阳膨胀土的水分特征和强度特性研究[J]. 水利学报, 2002(7): 87-92. (LIU Song-yu, MIAO Lin-chang.Soil-water characteristics and shear strength of expansive soil[J]. Journal of Hydraulic Engineering, 2002(7): 87-92. (in Chinese))
[13]	龚壁卫, 吴宏伟, 王斌. 应力状态对膨胀土SWCC的影响研究[J]. 岩土力学, 2004, 25(12): 1915-1918. (GONG Bi-wei, WU Hong-wei, WANG Bing.Influence of stress states on soil-water characteristics of expansive soils[J]. Rock and Soil Mechanics, 2004, 25(12): 1915-1918. (in Chinese))
[14]	GB/T 50123—1999土工试验方法标准[S]. 1999. (GB/T 50123—1999 Standard for soil test method[S]. 1999. (in Chinese))
[15]	GB50112—2013膨胀土地区建筑技术规范[S]. 2013. (GB50112—2013 Technical code for buildings in expansive soil regions[S]. 2008. (in Chinese))
[16]	吴宏伟, 陈锐. 非饱和土试验中的先进吸力控制技术[J]. 岩土工程学报, 2006, 28(2): 123-128. (NG C W W, CHEN Rui. Advanced suction control techniques for testing unsaturated soils[J]. Chinese Journal of Geotechnical Engineering, 2006, 28(2): 123-128.(in Chinese))
[17]	孙世国, 武崇福, 刘洋, 等. 土力学地基基础[M]. 北京:中国电力出版社, 2011: 15. (SUN Shi-guo, WU-Chong-fu, LIU Yang, et al. Soil mechanics and foundation[M]. Beijing: China Electric Power Press, 2011. (in Chinese))