| 干湿过程中膨胀土最大剪切模量及其预测 |
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| 引用本文： | 陈伟,孙德安,张俊然.干湿过程中膨胀土最大剪切模量及其预测[J].水文地质工程地质,2021,48(6):89-96. |
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| 作者姓名： | 陈伟 孙德安 张俊然 |
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| 作者单位： | 1.上海大学土木工程系，上海 200444 |
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| 基金项目： | 国家重点研发计划项目(2019YFC1509800) |
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| 摘 要： | 为了研究膨胀土在天然环境下的动力特性，本文利用装有弯曲元的三轴仪对南阳膨胀土原状样和重塑样进行了最大剪切模量的测试试验。试验包括在不同围压下的饱和原状南阳膨胀土最大剪切模量测试；将初始干密度相近的原状样和重塑样分别进行脱湿和吸湿，量测整个过程中最大剪切模量的变化，并结合孔隙比进行分析。试验结果表明:饱和南阳膨胀土的最大剪切模量随着围压增大而增大；脱湿过程中南阳膨胀土最大剪切模量与含水率关系曲线要高于吸湿过程的曲线，即最大剪切模量与含水率关系存在滞回特性，这主要是吸力作用的缘故；初始干密度相近条件下原状样的最大剪切模量比重塑样的要小，这是由于原状样内部存在较多大孔隙。本文最后对饱和土最大剪切模量公式进行改进，使之适用于非饱和原状南阳膨胀土最大剪切模量的预测。
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| 关 键 词： | 膨胀土 最大剪切模量 弯曲元 干湿 预测 |
| 收稿时间： | 2020-12-16 |
The maximum shear modulus of expansive soil during wetting-drying processes and its prediction |
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| Institution: | 1.Department of Civil Engineering, Shanghai University, Shanghai 200444, China2.Henan Province Key Laboratory of Rock and Soil Mechanics and Structural Engineering, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, China |
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| Abstract: | In order to examine the dynamic characteristics of expansive soil in natural environment, the maximum shear modulus of undisturbed and remoulded Nanyang expansive soil specimens were tested by using a triaxial apparatus equipping with a pair of bender element. The saturated undisturbed Nanyang expansive soil specimen was tested using the bender element to measure the maximum shear modulus under different confining pressures. The maximum shear modulus of the undisturbed and remoulded specimens with the same dry density were measured in wetting-drying processes and analyzed in combination with the void ratio. The test results indicate that the maximum shear modulus of the saturated Nanyang expansive soil increases with the increasing confining pressure. In the relationship between the maximum shear modulus and water content, the drying curve is higher than the wetting one. It is also found that there is hysteretic characteristics in the maximum shear modulus and water content relationship, which is mainly due to the suction effect. Under similar dry density the maximum shear modulus of undisturbed specimen is smaller than the remoulded one. The reason is that there are more large pores in the undisturbed soil. Finally, an existing formula for the saturated soils is improved for predicting the maximum shear modulus of the unsaturated and undisturbed Nanyang expansive soil. |
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