伊犁黄土冻融后的三轴力学行为

IF 2 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY
Chunmei Chu, Longwei Yang, Wenyu Cheng, Juncheng Wang, Xiang Wang
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引用次数: 0

摘要

黄土对水非常敏感,其性质受风化和其他因素的影响很大。伊犁地区广泛分布的黄土滑坡与季节性冻融效应密切相关。本研究对伊犁地区不同含水量的黄土样品进行了多次冻融循环试验,并进行了三轴剪切试验,以研究黄土的力学特性。利用扫描电子显微镜图像分析了黄土样品微观结构的变化,以揭示其背后的机理。结果表明,冻融循环对含水量较低的黄土样品(10%)的应力-应变曲线的破坏模式有显著影响,以六个循环为转折点,黄土样品从应变软化过渡到应变硬化,而含水量较高的黄土样品(18%)的应力-应变曲线则从强硬化过渡到弱硬化。随着冻融循环次数的增加,黄土的破坏强度和剪切强度参数逐渐降低,并在第 10 次循环后趋于稳定。此外,强度参数的劣化在第一个循环后最为显著,且内聚力的劣化程度远大于内摩擦角。随着冻融循环次数的增加,内聚力和内摩擦角分别呈现指数函数和多项式函数衰减关系,其拟合参数随含水率的增加而发生突变,以 14% 为转折点。显微镜扫描电镜显示,冻融后架空孔隙数量增加,颗粒间的点对点接触增加,这与黄土孔隙率的增加是一致的。这揭示了冻融循环导致黄土强度显著下降的根本原因。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Triaxial mechanical behaviours of Ili loess after freeze–thaw
Loess is strongly sensitive to water, and its properties are substantially affected by weathering and other factors. Loess landslides, which are widely distributed in Ili, are closely related to seasonal freeze–thaw effects. In this study, multiple freeze–thaw cycle tests were conducted on loess samples with different moisture contents from the Ili region, and triaxial shear tests were conducted to study mechanical characteristics of the loess. Variations in the microstructure of the loess samples were analysed using scanning electron microscopy images to reveal the underlying mechanisms. The results showed that the freeze–thaw cycles significantly influence failure mode of the stress–strain curve of loess samples with a lower moisture content of 10%, which transitioned from strain softening to strain hardening with six cycles as the turning point, whereas the stress–strain curve transitioned from strong to weak hardening for the loess samples with higher moisture content of 18%. As the number of freeze–thaw cycles increased, failure strength and shear strength parameters of loess gradually decreased, and tended to stabilize after the 10th cycle. In addition, strength parameters deterioration is most significant after the first cycle, and the degree of cohesion deterioration was much greater than that of internal friction angle. Cohesion and internal friction angle showed attenuation exponential function and polynomial function relationship, respectively, with the number of freeze–thaw cycles, and their fitting parameters underwent a sudden change with increasing moisture content, with 14% as the turning point. Microscopic SEM revealed that the number of overhead pores increased, and point–to–point contact between particles increased after freeze–thaw, which was consistent with increase in of loess porosity. This revealed the fundamental reason for the significant deterioration in loess strength caused by freeze–thaw cycles.
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来源期刊
Frontiers in Earth Science
Frontiers in Earth Science Earth and Planetary Sciences-General Earth and Planetary Sciences
CiteScore
3.50
自引率
10.30%
发文量
2076
审稿时长
12 weeks
期刊介绍: Frontiers in Earth Science is an open-access journal that aims to bring together and publish on a single platform the best research dedicated to our planet. This platform hosts the rapidly growing and continuously expanding domains in Earth Science, involving the lithosphere (including the geosciences spectrum), the hydrosphere (including marine geosciences and hydrology, complementing the existing Frontiers journal on Marine Science) and the atmosphere (including meteorology and climatology). As such, Frontiers in Earth Science focuses on the countless processes operating within and among the major spheres constituting our planet. In turn, the understanding of these processes provides the theoretical background to better use the available resources and to face the major environmental challenges (including earthquakes, tsunamis, eruptions, floods, landslides, climate changes, extreme meteorological events): this is where interdependent processes meet, requiring a holistic view to better live on and with our planet. The journal welcomes outstanding contributions in any domain of Earth Science. The open-access model developed by Frontiers offers a fast, efficient, timely and dynamic alternative to traditional publication formats. The journal has 20 specialty sections at the first tier, each acting as an independent journal with a full editorial board. The traditional peer-review process is adapted to guarantee fairness and efficiency using a thorough paperless process, with real-time author-reviewer-editor interactions, collaborative reviewer mandates to maximize quality, and reviewer disclosure after article acceptance. While maintaining a rigorous peer-review, this system allows for a process whereby accepted articles are published online on average 90 days after submission. General Commentary articles as well as Book Reviews in Frontiers in Earth Science are only accepted upon invitation.
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