Undrained Triaxial Compression Tests on Artificial CO2-hydrate-bearing Sand Specimens
Undrained Triaxial Compression Tests on Artificial CO2-hydrate-bearing Sand Specimens
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DOI：
10.1016/j.egypro.2017.03.1446
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发表时间：
2017-07
期刊：
影响因子：
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通讯作者：
Hiromasa Iwai;Y. Konishi;S. Kimoto
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文献类型：
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作者：
Hiromasa Iwai;Y. Konishi;S. Kimoto
全球变暖已被公认为全球范围内的严重问题之一，应立即加以解决。CO2捕集和封存技术被认为是减少植物和工业活动释放的温室气体的预期对策。近年来，一些研究者提出了一种新的CO2捕集和封存方法，即以CO2水合物的形式将CO2封存在海底。该方法是将CO2注入海底地面的桑迪层中，使CO2水合物能够稳定存在。为了实现安全和可持续的封存，它是必不可少的表征力学响应，如应力-应变关系或变形的CO2水合物的桑迪沉积物。在本研究中，我们进行了一系列的不排水三轴压缩试验的人工CO2水合物含砂标本。实验结果表明，含CO2水合物沉积物的刚度和抗剪强度均随CO2水合物含量的增加而增加，超静孔隙水压力降低，出现负超静孔隙水压力。孔隙中的CO2水合物似乎起着支撑土壤骨架的作用，它作为额外的砂粒增强了桑迪沉积物的膨胀行为。
Global warming has been recognized as one of the severe issues of global scale which should be addressed immediately. CO2capture and storage technologies have been believed to be an expected countermeasure for reduction of the greenhouse gas released by plants and industrial activities. Recently, a new method for CO2capture and storage has been proposed by some researchers, that is, CO2sequestration in the form of CO2-hydrate under the seafloor. In this method, CO2is injected into the sandy layer of seabed ground where the CO2-hydrate can exist stably. In order to achieve the safe and sustainable sequestration, it is essential to characterize the mechanical response such as stress-strain relationships or deformations of CO2-hydrate-bearing sandy sediments. In the present study, we have conducted a series of undrained triaxial compression tests on artificial CO2-hydrate-bearing sand specimens. From the experiment results, it is found that both stiffness and shear strength of CO2-hydrate-bearing sediments increase as increases in content of CO2-hydrates, and excess pore water pressure is reduced so that negative excess pore water pressure can be observed. The CO2-hydrates in the pore spaces seem to play a role of supporting the soil skeleton and it acts as additional sand particles which enhances the dilation behaviour of the sandy sediments.