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膨胀土完全软化强度指标试验研究

张坤勇, 徐娜, 陈恕, ENAMULLAHBaba Kalan, 谢宇飞

张坤勇, 徐娜, 陈恕, ENAMULLAHBaba Kalan, 谢宇飞. 膨胀土完全软化强度指标试验研究[J]. 岩土工程学报, 2020, 42(11): 1988-1995. DOI: 10.11779/CJGE202011003
引用本文: 张坤勇, 徐娜, 陈恕, ENAMULLAHBaba Kalan, 谢宇飞. 膨胀土完全软化强度指标试验研究[J]. 岩土工程学报, 2020, 42(11): 1988-1995. DOI: 10.11779/CJGE202011003
ZHANG Kun-yong, XU Na, CHEN Shu, ENAMULLAH Baba Kalan, XIE Yu-fei. Experimental study on fully softened shear strength of expansive soil[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(11): 1988-1995. DOI: 10.11779/CJGE202011003
Citation: ZHANG Kun-yong, XU Na, CHEN Shu, ENAMULLAH Baba Kalan, XIE Yu-fei. Experimental study on fully softened shear strength of expansive soil[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(11): 1988-1995. DOI: 10.11779/CJGE202011003

膨胀土完全软化强度指标试验研究  English Version

基金项目: 

国家自然科学基金项目 51578214

详细信息
    作者简介:

    张坤勇(1975—),男,教授,硕士生导师,主要从事土的基本特性,尤其是复杂应力状态下土体本构关系、边坡稳定分析等方面的教学和科研工作。E-mail:ky_zhang@hhu.edu.cn

  • 中图分类号: TU443

Experimental study on fully softened shear strength of expansive soil

  • 摘要: 以引江济淮试验段工程项目为依托,开展膨胀土完全软化强度试验,分析了膨胀土完全软化强度指标在不同含水率、剪切速率下的变化规律,并在此基础上与膨胀土干湿循环强度指标展开对比分析。完全软化状态下,膨胀土黏聚力接近0,完全软化强度主要由内摩擦角决定;内摩擦角受含水率影响不大且几乎不受剪切速率影响;黏聚力普遍较小,符合完全软化状态黏聚力接近0的定义。分别采用干湿循环后强度指标和完全软化强度指标,对简单膨胀土边坡开展了干湿循环后浅层稳定性分析。结果表明,和干湿循环试验相比,完全软化试验工作量小,试验周期短,能反映膨胀土边坡浅层滑塌的破坏机理,可用以对膨胀土边坡受干湿循环作用后的浅层稳定性分析。
    Abstract: The fully softened strength tests are carried out on the expansive soil samples from the Yangtze-Huaihe River Water Transfer Project. The fully softened strength indexes under different moisture contents and shear rates are discussed and analyzed. On this basis, they are compared with the shear strength indexes from the wetting-drying cycle direct shear tests on expansive soil. The results show that in the fully softened state, the cohesive force of expansive soil is close to zero, and the fully softened strength is mainly determined by the inernal friction angle. The inernal friction angle is little affected by the moisture content and shear rate. The strength indexes obtained from wetting-dring cycle tests and fully softened tests are applied to the safety analysis of simple expansive soil slope respectively. Compared with the wetting-drying cycle direct shear tests, the fully softened strenght tests need less lab work and shorter test peroid. The fully softened strength indexes can also reflect the failure mechanism of the shallow failure of expansive soil slopes after wetting-drying cycles in practice. It is recommended to apply the fully softened strength indexes in the analysis of the shallow stability of expansive soil slopes after wetting-drying cycles.
  • 图  1   峰值强度、残余强度及完全软化强度比较

    Figure  1.   Comparison among peak strength, residual strength and fully softened strength

    图  2   引江济淮试验段K41+600边坡膨胀土

    Figure  2.   Expansive soil at excavated slope in section K41+600

    图  3   重塑土小饼样

    Figure  3.   Pie-shaped remolded expansive soil sample

    图  4   完全软化样

    Figure  4.   Fully softened expansive soil sample

    图  5   四联应变控制式直剪仪

    Figure  5.   Strain-controlled direct shear apparatus

    图  6   抗剪强度与法向应力关系曲线

    Figure  6.   Relationship between shear strength and normal stress

    图  7   膨胀土完全软化样在各级法向应力下的抗剪强度

    Figure  7.   Fully softened shear strengths under different normal stress

    图  8   完全软化强度指标随土样含水率变化曲线

    Figure  8.   Relationship between fully softened strength indexes and moisture content

    图  9   膨胀土完全软化样在不同剪切速率下的剪切位移-剪应力的关系曲线

    Figure  9.   Relationship between shear stress and shear displacement under different shear rates

    图  10   不同强度指标计算膨胀土抗剪强度

    Figure  10.   Calculated values of shear strength with different indexes

    图  11   使用干湿循环强度指标的膨胀土边坡模型

    Figure  11.   Model of expansive soil slope usimg shear strength indexes from wetting-drying cycle tests

    图  12   使用完全软化强度指标的膨胀土边坡模型

    Figure  12.   Model of expansive soil slope using shear strength indexes from fully softened tests

    图  13   仅考虑干湿循环过程

    Figure  13.   Model only considering process of wetting-drying cycles

    图  14   仅考虑完全软化过程

    Figure  14.   Model only considering fully softened process

    表  1   完全软化试验设计方案

    Table  1   Programs of fully softened tests

    试验条件编号试样含水率/%剪切速率/(mm·min-1)
    #045.00.1,0.6,0.8,1.2
    #147.50.1,0.6,0.8,1.2
    #250.00.1,0.6,0.8,1.2
    #352.50.1,0.6,0.8,1.2
    #455.00.1,0.6,0.8,1.2
    下载: 导出CSV

    表  2   重塑样抗剪强度试验结果

    Table  2   Shear strength results of remolded soil

    法向应力/kPa干湿循环次数
    0135
    12.519.215.712.912.7
    25.023.217.917.817.6
    37.527.122.220.720.4
    50.030.626.524.324.3
    10032.328.627.726.9
    20036.332.929.229.0
    30038.934.633.532.9
    40042.338.435.836.1
    下载: 导出CSV

    表  3   重塑样抗剪强度指标

    Table  3   Shear strength indexes of remolded soil

    循环次数高应力段低应力段
    c/kPaϕ/(°)c/kPaϕ/(°)
    029.31.915.517.6
    125.91.911.416.4
    324.31.69.616.6
    523.61.89.316.7
    注:循环幅度为4%~31%,脱湿温度为40℃。
    下载: 导出CSV

    表  4   膨胀土完全软化强度指标

    Table  4   Fully softened shear strength indexes

    土样含水率w/%剪切速率/(mm·min-1)
    0.10.60.81.2
    c/kPaϕ/(°)c/kPaϕ/(°)c/kPaϕ/(°)c/kPaϕ/(°)
    45.02.425.22.125.21.925.21.724.8
    47.51.825.31.525.01.424.91.324.9
    50.01.324.81.124.61.124.80.924.4
    52.51.024.60.824.30.724.10.623.8
    55.00.924.40.824.20.623.90.523.8
    下载: 导出CSV

    表  5   边坡土体抗剪强度指标

    Table  5   Shear strength indexes of expansive soil slopes

    土体埋深/m初始强度指标干湿循环强度指标完全软化强度指标
    c/kPaϕ/(°)c/kPaϕ/(°)c/kPaϕ/(°)
    0~2.515.517.69.316.70.623.9
    2.5~4.029.31.923.61.8
    4.0~9.029.31.929.31.929.31.9
    下载: 导出CSV
  • [1]

    SKEMPTON A W. Long-term stability of clay slopes[J]. Géotechnique, 1964, 14(2): 77-102. doi: 10.1680/geot.1964.14.2.77

    [2]

    SKEMPTON A W. First-time slides in over-consolidated clays[J]. Géotechnique, 1970, 20(3): 320-324. doi: 10.1680/geot.1970.20.3.320

    [3]

    CHANDLER R J, SKEMPTON A W. The design of permanent cutting slopes in stiff fissured clays[J]. Géotechnique, 1974, 24(4): 457-466. doi: 10.1680/geot.1974.24.4.457

    [4]

    MORGENSTERN N. Slopes and excavations in heavily over-consolidated clays[C]//Proc 9th Int Conf on Soil Mechanics and Foundation Engineering, 1977, New York: 567-581.

    [5]

    STARK T D, EID H T. Slope stability analyses in stiff fissured clays[J]. J Geotech Geoenviron Eng, 1997, 123(4): 335-343. doi: 10.1061/(ASCE)1090-0241(1997)123:4(335)

    [6]

    MESRI G, SHAHIEN M. Residual shear strength mobilized infirst-time slope failures[J]. J Geotech Geoenviron Eng, 2003, 129(12): 12-31.

    [7]

    DUNCAN J M, BRANDON T, VANDEN Berge D. Report of the workshop on shear strength for stability of slopes in highly plastic clays[R]. Blacksburg: Center for geotechnical practice and research report, Virginia Polytechnic Institute and State University, 2001.

    [8]

    SRIDHARAN A, PRAKASH K. Classification procedures for expansive soils[J]. Geotechnical Engineering, 2000, 143(4): 235-240.

    [9] 廖世文. 膨胀土与铁路工程[M]. 北京: 中国铁道出版社, 1984.

    LIAO Shi-wen. Expansive Soil and Railway Engineering[M]. Beijing: China Railway Publishing House, 1984. (in Chinese)

    [10] 杨果林, 王永和, 李献民. 湘潭—邵阳高速公路膨胀土工程特性试验研究[J]. 铁道科学与工程学报, 2005, 2(1): 62-67. https://www.cnki.com.cn/Article/CJFDTOTAL-CSTD200501013.htm

    YANG Guo-lin, WANG Yong-he, LI Xia-min. Experimental study of engineering characteristic of expansive soils in the expressway of Xiangtan- Shaoyang[J]. Journal of Railway Science and Engineering, 2005, 2(1): 62-67. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-CSTD200501013.htm

    [11] 殷宗泽, 袁俊平, 韦杰, 等. 论裂隙对膨胀土边坡稳定的影响[J]. 岩土工程学报, 2012, 34(12): 2155-2161. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201212003.htm

    YIN Zong-ze, YUAN Jun-ping, WEI Jie, et al. Influences of fissures on slope stability of expansive soil[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(12): 2155-2161. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201212003.htm

    [12] 汪明元, 徐晗, 杨洪, 等. 非饱和膨胀土边坡破坏机理与稳定性分析[J]. 南水北调与水利科技, 2008(1): 151-153, 158. doi: 10.3969/j.issn.1672-1683.2008.01.040

    WANG Ming-yuan, XU Han, YANG Hong, et al. Analysis method of unsaturated expansive soils slope[J]. South-to-North Water Transfers and Water Science & Technology, 2008(1): 151-153, 158. (in Chinese) doi: 10.3969/j.issn.1672-1683.2008.01.040

    [13] 杨和平, 王兴正, 肖杰. 干湿循环效应对南宁外环膨胀土抗剪强度的影响[J]. 岩土工程学报, 2014, 36(5): 949-954. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201405027.htm

    YANG He-ping, WANG Xing-zheng, XIAO Jie. Influence of wetting-drying cycles on strength characteristics of Nanning expansive soils[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(5): 949-954. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201405027.htm

    [14]

    MESIR G, SHAHIEN M. Residual shear strengh mobilized in first-time slope failures[J]. Journal of Geotachnical and Geoenvironmental engineering, 2003, 129(1): 12-31.

    [15]

    BJERRUM L. Progressive failure in slope of overcnsolidated olastic clay and clay shales[J]. ASCE, 1967, 93(5): 3-49.

    [16]

    SKEMPTON A W. Slope stability of cutting in brown London clay[J]. Japanese Society of Social Mechanics and Foundation Engineering, 1977, 3: 261-270.

    [17]

    CHANDLER R J. Recent European experience of landslides in over-consolidated clays and rocks[C]//Proc 4th Int Symp On Landslides, 1984, Toronto.

    [18]

    CANCELLI A. Evaluation of slopes in over consolidated clays[C]//Proc 10th Int Conf Soil Mech and Found Engrg, 1981, Stockholm.

    [19]

    Binod Tiwari and Beena Ajmera. Laboratory measurement of fully softened shear strength and its application for landslide analysis[C]//Landslide Dynamics: ISDR-ICL Landslide Interactive Teaching Tools, 2018, USA.

    [20]

    Isaac Stephens and A1 Branch. Testing Procedure for Estimation Fully Softened Shear Strength of Soils Using Reconstituted Material[R]. ERDC/GSL GeoTACS TN-13-1. 2013.

    [21] 黄震, 傅鹤林, 韦秉旭, 等. 等幅干湿循环条件下膨胀土的低应力抗剪强度特征[J]. 四川大学学报(工程科学版), 2016, 48(1): 70-77. https://www.cnki.com.cn/Article/CJFDTOTAL-SCLH201601011.htm

    HUANG Zhen, FU He-lin, WEI Bing-xu, et al. Low stress shear strength characteristics of expansive soil under constant amplitude dry wet cycle conditions[J]. Journal of Sichuan University (Engineering Science Edition), 2016, 48(1): 70-77. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SCLH201601011.htm

    [22] 程展林, 李青云, 郭熙灵, 等. 膨胀土边坡稳定性研究[J]. 长江科学院院报, 2011, 28(10): 102-111. https://www.cnki.com.cn/Article/CJFDTOTAL-CJKB201110019.htm

    CHENG Zhan-lin, LI Qing-yuan, GUO Xi-ling, et al. Study on the stability of expansive soil slope[J]. Journal of Yangtze River Scientific Research Institute, 2011, 28(10): 102-111. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-CJKB201110019.htm

    [23]

    TIKA T E, LAMOS L J, VAUGHAN P R. Fast shearing of pre-existing shear zones in soil[J]. Géotechnique, 1996, 46(2): 197-233.

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出版历程
  • 收稿日期:  2019-09-02
  • 网络出版日期:  2022-12-05
  • 刊出日期:  2020-10-31

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