| 非饱和黄土强度参数的试验研究 |
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| 引用本文： | 邢鲜丽,李同录,巨昆仑,付昱凯,习羽.非饱和黄土强度参数的试验研究[J].工程地质学报(英文版),2015,23(2):252-259. |
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| 作者姓名： | 邢鲜丽 李同录 巨昆仑 付昱凯 习羽 |
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| 作者单位： | 长安大学地质工程与测绘学院 西安 710054 |
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| 基金项目： | 国家自然科学基金项目，973项目(2014CB744701)资助． |
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| 摘 要： | 非饱和土强度理论的研究是非饱和土力学的核心问题。目前公认的非饱和土强度理论是Bishop的单变量理论和Fredlund的双变量理论,二者都引入了基质吸力这一应力参数,只是前者将其归到有效应力中,后者作为独立变量。要得到这两个公式中相关参数需利用控制基质吸力的非饱和土三轴仪或直剪仪测定,控制基质吸力是通过同步增加气压和孔隙水压力保持吸力不变实现的,即所谓的轴平移技术,该项技术一直面临测试周期长的困难和合理性的质疑。鉴于此,本文采用不同含水率的常规三轴CU试验,测定了有效稳态强度参数,得出了吸应力和体积含水率的关系曲线,非饱和强度直接用吸应力函数表达,该强度公式回避了测定基质吸力的问题,便于在工程实际中推广。为了进一步和Bishop及Fredlund的强度公式进行对比,又用张力计测定了同一试样的水土特征曲线,获得了其强度参数。理论上,这3种强度理论对机理的解释不同,但在数学上可以互相转化。从工程应用的角度,基于吸应力的抗剪强度更便于工程应用。
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| 关 键 词： | 非饱和土 水土特征曲线 基质吸力 吸应力 吸应力特征曲线 |
| 收稿时间： | 2014-04-01 |
RESEARCH ON THE STRENGTH PARAMETERS OF UNSATURATED LOESS |
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| XING Xianli,LI Tonglu,JU Kunlun,FU Yukai,XI Yu.RESEARCH ON THE STRENGTH PARAMETERS OF UNSATURATED LOESS[J].Journal of Engineering Geology,2015,23(2):252-259. |
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| Authors: | XING Xianli LI Tonglu JU Kunlun FU Yukai XI Yu |
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| Institution: | School of Geological Engineering and Geomatics, Chang'an University, Xi'an 710054 |
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| Abstract: | The study on strength theory of unsaturated soil is the core of the research in the field of unsaturated soil mechanics. In the early time, Bishop's univariate strength theory and Fredlund's bivariate strength theory are the most classical strength theories for unsaturated soil. Both introduce the matric suction as stress parameter. However, it attributes to effective stress in the former and it is an independent variable in the latter. Matric suction controlled unsaturated triaxial or direct shear apparatus are needed in order to get the related parameters in the two formulas. The controlling of matric suction needs synchronized increase of pore air pressure and pore water pressure so as to keep the matric suction constant, which is so called axis-translation technique. However, problems such as long process and its feasibility doubts still exist in axis parallel translation technique. Therefore, conventional triaxial CU test with different moisture content is used to get the effective steady state strength parameters. Then the suction stress characteristic curve is obtained on the basis of the suction stress concept. The shear strength formula is expressed as a function of suction stress which significantly avoids the determination of matric suction. Therefore, it is convenient for widely application in engineering practice. In order to make a further compare with the unsaturated strength of Bishop and Fredlund, the soil water characteristic curve of the same sample determined by tensiometer is used to get their strength parameters. In theory, these three strength theories are different in the mechanism explanation, but they can transform to each other in mathematics. From the perspective of engineering applications, shear strength theory, based on suction stress, is more convenient to apply in engineering. |
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| Keywords: | Unsaturated soil Soil water characteristic curve Matric suction Suction stress SSCC |
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