Thermo-mechanical volume change behaviour of Opalinus Clay
Thermo-mechanical volume change behaviour of Opalinus Clay
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DOI：
10.1016/j.ijrmms.2016.09.013
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发表时间：
2016-12
影响因子：
7.2
通讯作者：
V. Favero;A. Ferrari;L. Laloui
中科院分区：
文献类型：
--
作者：
V. Favero;A. Ferrari;L. Laloui
本文研究了Opalinus粘土的热机械体积变化行为在不同的应力条件和超固结比（OCR）值，并评估温度对这种材料的一些流体力学性能的影响。为此，进行了一项集中的实验活动，包括高温/高压体积测量试验。结果表明，Opalinus粘土的热机械体积变化行为是严重影响的OCR：热膨胀时，发现在高OCR下进行加热，而不可逆的热压实时，观察到热施加在垂直有效应力，这是足够接近的垂直有效屈服应力。热循环行为的研究表明，膨胀不可逆的应变可以发生在第一次加热时，在高OCR和可逆的行为，随后在随后的热循环。实验结果揭示了温度对屈服的影响：当在高温下施加压缩时，相对于在低温下发现的屈服阈值，检测到屈服阈值的降低。压缩性和膨胀指数没有显着的热变化的影响，以及oedometric模量和二次压缩系数，而固结过程中发现在高温下发生得更快。所获得的结果在本文中连同所采用的测试装置和实验程序的描述。
The paper examines the thermo-mechanical volume change behaviour of Opalinus Clay in relation to different stress conditions and overconsolidation ratio (OCR) values and evaluates the impact of temperature on some hydro-mechanical properties of this material. To this aim, a focused experimental campaign consisting in high-temperature/high-pressure oedometric tests has been carried out. The results show that the thermo-mechanical volume change behaviour of Opalinus Clay is heavily affected by the OCR: thermal expansion is found when the heating is carried out at high OCR, whereas irreversible thermal compaction is observed when heat is applied at a vertical effective stress that is sufficiently close to the vertical effective yield stress. The study of the thermal cyclic behaviour shows that expansive irreversible strains can occur upon first heating at high OCR and that a reversible behaviour follows during subsequent thermal cycles. The experimental results reveal an impact of temperature on yielding: a decrease in the yield threshold is detected when compression is applied at high temperature with respect to the yield threshold found at low temperature. Compressibility and swelling indexes are not significantly influenced by thermal changes, as well as the oedometric modulus and the secondary compression coefficient, whereas consolidation processes are found to occur faster at high temperature. The obtained results are presented in this paper together with a description of the testing device and experimental procedure employed.