| 石灰稳定红黏土强度的长期碳化效应 |
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| 引用本文： | 谈云志,喻 波,郑 爱,付 伟,张 华,万 智.石灰稳定红黏土强度的长期碳化效应[J].岩土力学,2013,34(Z1):73-79. |
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| 作者姓名： | 谈云志 喻 波 郑 爱 付 伟 张 华 万 智 |
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| 作者单位： | 1. 三峡大学 三峡库区地质灾害教育部重点实验室，湖北 宜昌443002；2. 中交第二公路勘察设计研究院有限公司，武汉 430056； 3. 湖南省交通科学研究院，长沙 410015 |
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| 基金项目： | 国家自然科学基金资助（No.51009084）；湖南省交通运输厅科技进步与创新计划资助（No.200910，No.201045） |
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| 摘 要： | 碳化效应是石灰稳定土强度增长机理之一，但长期的碳化作用是否对其强度一直起促进作用？如果没有压实作用，碳化效果到底如何？这些关键问题还没有得到充分的论证。采用灰土拌和后击实养护和养护后再击实的不同制样方法，通过承载比CBR试验，探讨压实作用对碳化效应的影响。制备4种初始含水率的击实试样，开展碳酸溶液和纯水浸泡下的CBR试验，论证长期碳化对石灰稳定土强度的作用效果。结果表明，自然养护90 d后再击实试样的CBR值明显低于击实后养护的试样；初始含水率为34%时前者约为后者的12倍。另外，碳酸溶液浸泡15 d后的试样CBR值均小于纯水浸泡的试样CBR值，但初始含水率越大其影响程度越小，当初始含水率大于34%后两者之间的强度基本没有差别。为进一步佐证长期碳化作用能弱化石灰稳定土的强度，开展不同浸泡时间的无侧限抗压强度试验，发现石灰土的强度呈现先增大后减少的变化趋势，再次证实长期的碳化作用弱化石灰稳定土的强度。最后，利用热重分析法测试经过碳酸溶液浸泡前后的石灰稳定土，发现长期碳化溶解了部分石灰土中的碳酸钙和硅酸盐类胶结物。借助扫描电镜图片和孔隙尺寸分布曲线，从微观角度揭示不同击实和养护方式对石灰稳定土强度的影响机制。
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| 关 键 词： | 石灰稳定土 碳化效应 长期作用 红黏土 |
| 收稿时间： | 2012-12-10 |
Long-term carbonated effect on strength of lime stabilized laterite soils |
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| TAN Yun-zhi,YU Bo,ZHENG Ai,FU Wei,ZHANG Hua,WAN Zhi.Long-term carbonated effect on strength of lime stabilized laterite soils[J].Rock and Soil Mechanics,2013,34(Z1):73-79. |
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| Authors: | TAN Yun-zhi YU Bo ZHENG Ai FU Wei ZHANG Hua WAN Zhi |
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| Institution: | 1. Key Laboratory of Geological Hazards in Three Gorges Reservoir Area of Ministry of Education, China Three Gorges University, Yichang, Hubei 443002, China; 2. China Commnnications Construction Corporation Second Highway Consulfans, Co. Ltd., Wuhan 430056, China; 3. Hunan Communications Research Institute, Changsha 410015, China |
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| Abstract: | Carbonation is one of the strength enhanced mechanism for lime stabilized soil. But there has many major problems need solution. For example, whether the long-term carbonation is always beneficial to its strength? If limed soil were not compacted tightly, how about was the carbonated effect of it? So, California bearing ratio CBR tests were performed to evaluated the influence of compacted degree on carbonated effect by preparation samples under curing before and after compacted conditional. And also, CBR tests were carried out to prove the long-term carbonation effect on the strength of lime stabilized soil by analyzing the strength variation of four kinds of initial water contents compacted specimens which were under immersion in carbonate solution and pure water separately. The results show that the CBR values of sample compacted after natural curing 90 days are significantly lower the strength of samples which compacted before curing, when their initial moisture content is 34.0%; the former CBR are about 12 times as the later ones. And, the CBR of samples immersion in carbonic acid solution 15 days are less than pure water immersion ones. But, the higher initial water content is, the smaller the influence is. For example, the initial moisture content is greater than 34.0%, the CBR values are obviously difference between them. In addition, it carried out unconfined compressive strength test under different soaking times, the results further evidence that long-term carbonation can reduce the strength of stabilized soil. Finally, thermo-gravimetric analysis tests are performed to the limed soil to determine the content of calcium carbonate and to evaluate whether or not there are degradation and migration after soaking in carbonate solution. And, it reveals the effect mechanism of different compactions and curing methods on the strength of lime stabilization by scanning electron microscopy photographs and pore size distribution curves. |
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| Keywords: | lime stabilized soil carbonated effect long-term effect laterite soil |
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