Quantifying irreversible movement in steep, fractured bedrock permafrost on Matterhorn (CH)
Quantifying irreversible movement in steep, fractured bedrock permafrost on Matterhorn (CH)
复制标题
量化马特洪峰（瑞士）陡峭、破碎的基岩永久冻土层中的不可逆运动
DOI：
10.5194/tc-11-567-2017
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
A. Vieli
中科院分区：
文献类型：
--
作者：
S. Weber;J. Beutel;J. Faillettaz;A. Hasler;M. Krautblatter;A. Vieli
抽象的。了解岩石边坡运动学陡峭，破碎基岩永久冻土是一项具有挑战性的任务。最近的实验室研究提供了在寒冷环境中岩石疲劳和断裂的理解，但没有成功地证实了现场研究。这项研究提出了一个独特的时间序列的断裂运动学，岩石温度和环境条件在3500米a.s.l.陡峭，强烈断裂Hornligrat的马特宏峰（瑞士阿尔卑斯山）。 得益于8年的连续数据，可以以前所未有的详细程度分析永久冻土断裂运动学的长期演变。断裂运动学的时空模式的共同趋势的证据可以被发现：部分可逆的季节性运动可以观察到在所有位置，具有可变的振幅。在更广泛的背景下，岩石边坡稳定性评估，我们建议分离可逆（弹性）组件的断裂运动学，热弹性应变所造成的，从不可逆（塑性）组件由于其他过程。温度和裂缝位移之间的回归分析表明，所有仪器骨折表现出可逆的位移，占主导地位的骨折运动学在冬季。此外，从观察到的位移中去除这个可逆分量使我们能够量化不可逆分量。由此，提出了一种新的度量-称为不可逆性指数-来量化裂缝运动学的相对不可逆性。这个新的指数可以识别断裂位移由不可逆过程主导的时期。对于许多传感器，在夏季观察到不可逆的增强断裂位移，并且其开始与正岩石温度的开始一致。这可能表明与解冻有关的过程，如融水渗透到裂缝中，作为不可逆位移的强制机制。对于一些仪器断裂，不可逆的位移被发现在冻结期的开始，这表明低温过程作为一个驱动因素，通过增加冰压力。所提出的分析提供了一个工具，调查和更好地了解有关的不可逆运动过程。
Abstract. Understanding rock slope kinematics in steep, fractured bedrock permafrost is a challenging task. Recent laboratory studies have provided enhanced understanding of rock fatigue and fracturing in cold environments but were not successfully confirmed by field studies. This study presents a unique time series of fracture kinematics, rock temperatures and environmental conditions at 3500 m a. s. l. on the steep, strongly fractured Hornligrat of the Matterhorn (Swiss Alps). Thanks to 8 years of continuous data, the longer-term evolution of fracture kinematics in permafrost can be analyzed with an unprecedented level of detail. Evidence for common trends in spatiotemporal pattern of fracture kinematics could be found: a partly reversible seasonal movement can be observed at all locations, with variable amplitudes. In the wider context of rock slope stability assessment, we propose separating reversible (elastic) components of fracture kinematics, caused by thermoelastic strains, from the irreversible (plastic) component due to other processes. A regression analysis between temperature and fracture displacement shows that all instrumented fractures exhibit reversible displacements that dominate fracture kinematics in winter. Furthermore, removing this reversible component from the observed displacement enables us to quantify the irreversible component. From this, a new metric – termed index of irreversibility – is proposed to quantify relative irreversibility of fracture kinematics. This new index can identify periods when fracture displacements are dominated by irreversible processes. For many sensors, irreversible enhanced fracture displacement is observed in summer and its initiation coincides with the onset of positive rock temperatures. This likely indicates thawing-related processes, such as meltwater percolation into fractures, as a forcing mechanism for irreversible displacements. For a few instrumented fractures, irreversible displacements were found at the onset of the freezing period, suggesting that cryogenic processes act as a driving factor through increasing ice pressure. The proposed analysis provides a tool for investigating and better understanding processes related to irreversible kinematics.
不稳定高山基岩永久冻土的研究前景：测量、建模和过程理解
影响因子：
5
作者：
Krautblatter;Huggel;Deline P;Hasler A.
通讯作者：
Hasler A.
季节性间歇性水流穿过高山岩脊的深层裂缝：瑞士中部阿尔卑斯山的 Gemsstock
影响因子：
4.1
作者：
Phillips;Haberkorn;Draebing;Krautblatter;Rhyner;R. Kenner
通讯作者：
R. Kenner