| 摘要: |
| 【目的】研究膨胀潜势、含水率对膨胀土抗剪强度的影响，为膨胀土强度理论研究及其工程应用提供参考。【方法】采用固结不排水试验方法，通过TFB 1型非饱和土应力应变控制式三轴仪，分别测定取自陕西汉中、安康的2种膨胀土样及2种土样1∶1（质量比）混合土（简称汉中土、安康土、混合土）3种不同膨胀潜势的膨胀土在不同含水率下的抗剪强度指标，应用Microsoft Excel软件，绘制3种膨胀土的抗剪强度指标与含水率、自由膨胀率的关系曲线，探讨膨胀土抗剪强度与含水率、膨胀潜势的关系及变化趋势。【结果】3种膨胀土的含水率与非饱和膨胀土的抗剪强度指标呈负相关关系，当含水率由12%增大到24%时，汉中土、混合土、安康土3种膨胀土的黏聚力分别降低56.83，53.74和61.61 kPa，三者的内摩擦角分别降低7.87°，9.12°和9.58°；3种膨胀土的膨胀潜势与非饱和膨胀土的抗剪强度指标呈正相关关系，汉中土、混合土、安康土的膨胀潜势依次减弱，当三者分别处于同一含水率（12%，15%，18%，21%和24%）时，汉中土、混合土、安康土的抗剪强度指标依次减小。【结论】非饱和膨胀土的抗剪强度与含水率、膨胀潜势密切相关。 |
| 关键词: 膨胀土 膨胀潜势 自由膨胀率 抗剪强度 |
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| Strength characteristics of expansive soil |
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JIA Wen-cong,LI Yong-hong,DANG Jin-qian,et al
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| Abstract: |
| 【Objective】The paper studied the influences of expansion potential and water content on shear strength of expansive soil to provide reference for strength theory and engineering application.【Method】Shear strength indexes of three expansive soils with different expansion potentials obtained from Ankang,Hanzhong and their 1∶1 mixed soils (Hereafter referred as Hanzhong soil,Ankang soil and Composite soil) under different water contents were determined using consolidated undrained method and TFB-1 stress-strain triaxial apparatus of unsaturated soil.Then,the relationship between shear strength and water content and expansion potential was discussed and the variation was analyzed.【Result】Negative correlations existed between water contents and the shear strength indexes of the unsaturated expansive soils.When the water contents increased from 12% to 24%,the cohesive forces of Hanzhong soil,Composite soil and Ankang soil decreased by 56.83,53.74 and 61.61 kPa and the angle of frictions decreased by 7.87°,9.12° and 9.58°,respectively. Positive correlation existed between expansion potentials and shear strength indexes of the unsaturated expansive soils.The expansion potentials of Hanzhong soil,Composite soil and Ankang soil decreased successively.When the water contents were same (12%,15%,18%,21% and 24%),the shear strength indexes of Hanzhong soil,Composite soil and Ankang soil also decreased successively.【Conclusion】The shear strength of unsaturated expansive soil closely related to water content and expansion potential. |
| Key words: expansive soil expansion potential free expansion rate shear strength |
