| 不同类型黏土的强度特性及其预测 |
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| 引用本文： | 陈嘉伟,高游,付俊杰,李东映.不同类型黏土的强度特性及其预测[J].水文地质工程地质,2020,47(3):101-106. |
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| 作者姓名： | 陈嘉伟 高游 付俊杰 李东映 |
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| 基金项目： | 国家自然科学基金项目资助（41902279）；浙江省自然科学基金项目资助(LQ19E080006) |
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| 摘 要： | 强度特性是非饱和土力学中基础性的研究内容。目前对广吸力范围内非饱和黏土强度的预测研究相对较少。本文首先基于文献中粉质黏土、Madrid黏土和南阳弱膨胀土的非饱和强度特性进行了对比与分析。将不同类型非饱和黏土的强度特性大致分为3种类型:（1）在某一吸力范围试样出现强度峰值，并随着吸力值的进一步增大而降低；（2）达到某一吸力值后其强度几乎维持不变，不受吸力值的影响；（3）其强度随着吸力值的增大而增大。此外，基于现有考虑吸附水膜和毛细水作用的方法拟合广吸力范围内不同类型土的土水特征曲线，并将土水特征曲线分离成吸附土水特征曲线和毛细土水特征曲线。在非饱和土的抗剪强度公式中，认为吸力引起的非饱和强度增强部分主要由毛细水作用决定的，故将非饱和抗剪强度公式中吸力引起非饱和增强项的有效应力系数（即饱和度或有效饱和度）用毛细水对应的饱和度替代。最后，利用修正后的非饱和抗剪强度公式对3种较广吸力范围内非饱和土的强度进行了预测。预测结果表明过渡区段内的强度预测效果较好，但高吸力段非饱和强度的预测还有待进一步研究。
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| 关 键 词： | 非饱和土 强度 土水特征曲线 毛细水 预测 |
| 收稿时间： | 2019-09-11 |
Strength of different clayey soils and its prediction |
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| Abstract: | The shear strength of unsaturated soils is a fundamental property in the unsaturated soil mechanics. A systematical study of the strength behavior of the silty clay, Madrid clay and Nanyang weakly expansive soils in the literatures is carried out in this paper. The strength characteristics can be divided into three types: the peak value of shear strength appears in a certain suction range, the strength is almost not affected by suction after reaching a certain suction value, and its strength increases with the increasing suction during shearing. In addition, the method based on capillary action and water film absorption is used to fitting the soil water characteristic curve (SWCC) in the full suction range. This method can separate the capillary water characteristic curve from the absorption water characteristic curve. The capillary water plays a key role in the strength component caused by imposed suction in the unsaturated soil. The strength equation for the unsaturated soils can be modified by the capillary component of degree of saturation. Finally, the modified shear strength criterion is used to predict the strength of soils of the three different types in a wide range of suction. The predicted results can capture well the measured test data in the transition zone, but further studies are necessary to predict the shear strength for different soil types in a high suction range. |
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