The liquefaction of clayey soils under cyclic loading
The liquefaction of clayey soils under cyclic loading
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DOI：
10.1016/j.enggeo.2006.04.006
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发表时间：
2006-07
影响因子：
7.4
通讯作者：
I. Gratchev;K. Sassa;V. Osipov;V. N. Sokolov
中科院分区：
文献类型：
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作者：
I. Gratchev;K. Sassa;V. Osipov;V. N. Sokolov
本文旨在研究粘性土的液化，这是一种在过去几十年中引发许多自然灾害的现象，包括山体滑坡。对从地震诱发滑坡滑动面采集的人工粘土-砂混合物和天然粘性土进行了研究。利用环剪仪研究了正常固结粘性土在循环荷载作用下的不排水响应。对于人工粘土-砂混合物，发现少量膨润土（≤7%）的存在会引起快速液化，而进一步增加膨润土含量（≥11%）则会产生相反的效果，使土的抗液化能力显著提高。结果表明，在粘土含量相同的情况下，膨润土-砂混合物比高岭土-和伊利石-混合物更能抵抗液化。塑性土的试验结果表明，塑性对土的抗液化能力有显著影响。用扫描电镜研究了粘性土的微组构。分析表明，土的液化势与一定的颗粒排列方式密切相关。例如，易液化的土壤具有开放的微组构，其中粘土聚集体通常聚集在砂粒接触点处，形成低强度的“粘土桥”，在循环载荷期间容易被破坏。另一方面，抗液化的土壤微结构似乎更紧密，粘土产生了一种基质，防止沙粒液化。在天然土的情况下，所获得的结果表明，它们的循环行为类似的影响因素，如粘土含量，粘土矿物和塑性。从而建立了天然土的液化势与其微组构之间的关系。在此基础上，对粘性土液化机理提出了解释。
This paper seeks to investigate the liquefaction of clayey soils, a phenomenon that has been the trigger for many natural disasters in the last few decades, including landslides. Research was conducted on artificial clay–sand mixtures and natural clayey soils collected from the sliding surfaces of earthquake-induced landslides. The undrained response of normally consolidated clayey soils to cyclic loading was studied by means of a ring-shear apparatus. For the artificial clay–sand mixtures, it was found that the presence of a small amount of bentonite (≤7%) would cause rapid liquefaction, while a further increase in bentonite content (≥11%) produced the opposite effect of raising soil resistance to liquefaction by a significant degree. It was demonstrated that the bentonite–sand mixture was considerably more resistant to liquefaction than the kaolin-, and illite-mixtures, given the same clay content. The test results of plastic soils revealed the significant influence of plasticity on the liquefaction resistance of soil. The microfabric of clayey soil was investigated by means of a scanning electron microscope. The analysis showed that the liquefaction potential of soil was strongly related to certain particle arrangements. For example, soil vulnerable to liquefaction had an open microfabric in which clay aggregations generally gathered at the sand particle contact points, forming low-strength “clay bridges” that were destroyed easily during cyclic loading. On the other hand, the microfabric of soil that was resistant to liquefaction appeared to be more compact, with the clay producing a matrix that prevented sand grains from liquefying. In the case of the natural soils, the obtained results indicated that their cyclic behavior was similarly influenced by factors such as clay content, clay mineralogy and plasticity. The relation between the liquefaction potential of natural soil and its microfabric was thus also established. On the basis of the obtained results, the authors posited an explanation on the mechanism of liquefaction for clayey soil.