| 过量石灰对细粒土改良效果“负效应”机理的宏-细观试验研究 |
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| 引用本文： | 王章琼,白俊龙,叶张颜.过量石灰对细粒土改良效果“负效应”机理的宏-细观试验研究[J].武汉工程大学学报,2020,42(3):316-320. |
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| 作者姓名： | 王章琼 白俊龙 叶张颜 |
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| 作者单位： | 1. 武汉工程大学土木工程与建筑学院，湖北 武汉 430074；2. 恩施市公路管理局，湖北 恩施 445000 |
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| 摘 要： | 石灰是常用的特殊土改良材料，但掺量过大时反而导致改良土力学性质的劣化。为研究石灰掺量对细粒土改良效果“负效应”的产生机理，制备石灰掺杂质量分数为0%、3%、5%、7%、9%、11%的改良红砂岩残积土试样，分别养护28、60 d后进行无侧限抗压试验、扫描电子显微镜试验，获得无侧限抗压强度与石灰掺量和养护龄期的关系，以及不同石灰掺量改良土试样的微观结构特征。结果表明:对于本文试验中红砂岩残积土，无侧限抗压强度对应的最优石灰掺量为11%；石灰掺加质量分数不高于11%时，石灰充填在土颗粒孔隙中，起胶结土颗粒的作用，无侧限抗压强度提高；石灰掺加质量分数达到13%时，充填的石灰厚度过大，土颗粒“悬浮”在石灰之中，对承受轴向荷载的贡献大大减弱。
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| 关 键 词： | 土质改良 石灰 微观结构 细粒土 扫描电子显微镜 |
Mechanism of Negative Effect of Excessive Lime Addition on Improvement of Fine Grained Soil by Macro-Microscopic Test |
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| Authors: | WANG Zhangqiong BAI Junlong YE Zhangyan |
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| Affiliation: | 1. School of Civil Engineering and Architecture，Wuhan Institute of Technology，Wuhan 430074， China；2. Enshi Municipality Highway Bureau， Enshi 445000， China |
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| Abstract: | Lime is commonly used as the material to improve special soil，however，excessive amount of lime may deteriorate mechanical properties of improved soil. To study the mechanism of the effect of lime amount on the improvement of fine grained soil，the modified residual soil of red sandstone samples with lime mass fractions of 0，3%，5%，7%，9% and 11% were prepared. The samples were tested by the unconfined compression and scanning electron microscopy respectively after conservation of 28 d or 60 d. The relationship between unconfined compressive strength，lime amount and curing age，as well as the microstructure characteristics of modified soil samples were obtained. The result shows that the maximum unconfined compressive strength is achieved with 11% of lime amount，and lime is found to be filled in the pores of soil particles and cements the soil particles with less than 11% of lime amount，which increases the unconfined compressive strength. However，the filling lime is too thick with 13% of lime amount，thus the soil particles are "suspended" in lime，reducing axial load of soil particles. |
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| Keywords: | soil improvement lime microstructure fine grained soil scanning electron microscope |
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