Cold Regions Science and Technology最新文献

Hysteresis of unfrozen water content of tailing mud with freeze-thaw and its correlation with electrical conductivity 尾矿泥浆未冻含水量随冻融作用的滞后及其与电导率的相关性

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-13 DOI: 10.1016/j.coldregions.2024.104362

Wanying Xu , Fangtao She , Weibin Zeng , Songhe Wang , Jiulong Ding , Xiaoliang Yao , Guoping Liu , Lei Li

Identifying the correlation between the hysteresis of unfrozen water content and the electrical conductivity (EC) of tailing mud with freeze-thaw is essential for determining the range of frost hazards in tailings ponds by field conductivity measurement and enabling targeted treatment in coastal and seasonally frozen areas. In this study, dynamics of unfrozen water content and temperature of saturated tailing mud samples with 0.0–5.0 % NaCl were evaluated with 5TM sensor while the EC with the frequency domain reflectometry (FDR) sensor. Results show that unfrozen water hysteresis of tailing mud with freeze-thaw occurred below phase-change temperatures, with the cooling section above the warming. The area of hysteresis curve rose upon higher salinity or fewer freeze-thaw cycles. Phase-change temperatures of tailing mud, including freezing and thawing points, depressed with higher salinity but were less affected by freeze-thaw cycles, with the former coinciding with the liquidus line of NaCl solution while the latter located above. The EC curve also exhibits hysteresis with freeze-thaw and the initial salinity determines both the maximum EC value and the slope logEC/T below phase-change temperatures. It was concluded that the unfrozen water content, converted salt concentration and EC of frozen tailing mud show synchronous changes. A modified Michalowski model, with phase-change temperatures and residual unfrozen water content respectively simplified as proportional and exponential functions of initial salinity, was established to characterize the unfrozen water hysteresis of tailing mud with freeze-thaw cycles. A simple EC model with hysteresis was then developed by approximating the EC of frozen tailing mud as a power function of the converted salt concentration, which was applied to the tailing mud with 0.5–5.0 % NaCl in the range of −20 °C up to phase-change temperatures.

要想通过现场电导率测量确定尾矿库的冰冻危害范围，并在沿海和季节性冰冻地区进行有针对性的处理，就必须找出尾矿泥未冻结含水量滞后与电导率（EC）冻融之间的相关性。在这项研究中，使用 5TM 传感器评估了含 0.0-5.0 % NaCl 饱和尾矿泥样品的解冻水含量和温度动态，同时使用频域反射仪 (FDR) 传感器评估了导电率。结果表明，尾泥在冻融过程中的未冻水滞后发生在相变温度以下，冷却段高于升温段。盐度越高或冻融周期越短，滞后曲线的面积越大。尾矿泥浆的相变温度（包括冰点和融点）随盐度升高而降低，但受冻融循环的影响较小，前者与氯化钠溶液的液相线重合，而后者则位于其上方。导电率曲线还表现出冻融滞后现象，初始盐度决定了最大导电率值和相变温度以下的斜率 logEC/T。结论是，冻结尾矿泥浆的解冻含水量、转化盐浓度和导电率呈现同步变化。建立了一个改进的 Michalowski 模型，将相变温度和残余未冻结水含量分别简化为初始盐度的比例函数和指数函数，以描述冻融循环尾泥未冻结水滞后的特征。然后，通过将冻结尾泥的导电率近似为转换盐浓度的幂函数，建立了具有滞后性的简单导电率模型，该模型适用于-20 °C至相变温度范围内含0.5-5.0 % NaCl的尾泥。

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引用次数: 0

Metrological approach for permafrost temperature measurements 冻土温度测量的计量方法

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-10 DOI: 10.1016/j.coldregions.2024.104364

Graziano Coppa , Francesca Sanna , Luca Paro , Chiara Musacchio , Andrea Merlone

Permafrost degradation is a growing direct impact of climate change. Detecting permafrost shrinkage, in terms of extension, depth reduction and active layer shift is fundamental to capture the magnitude of trends and address actions and warnings. Temperature profiles in permafrost allow direct understanding of the status of the frozen ground layer and its evolution in time. The Sommeiller Pass permafrost monitoring station, at about 3000 m of elevation, is the key site of the regional network installed in 2009 during the European Project “PermaNET” in the Piedmont Alps (NW Italy). The station consists of three vertical boreholes with different characteristics, equipped with a total of 36 thermistors distributed in three different chains. The collected raw data shows a degradation of the permafrost base at approximately 60 m of depth since 2014, corresponding to about 0.03 °C/yr. In order to verify and better quantify this potential degradation, three on-site sensor calibration campaigns were carried out to understand the reliability of these measurements. By repeating calibrations in different years, two key results have been achieved: the profiles have been corrected for errors and the re-calibration allowed to distinguish the effective change of permafrost temperatures during the years, from possible drifts of the sensors, which can be of the same order of magnitude of the investigated thermal change. The warming of permafrost base at a depth of ∼ 60 m has been confirmed, with a rate of (4.2 ± 0.5)∙10⁻² °C/yr. This paper reports the implementation and installation of the on-site metrology laboratory, the dedicated calibration procedure adopted, the calibration results and the resulting adjusted data, profiles and their evolution with time. It is intended as a further contribution to the ongoing studies and definition of best practices, to improve data traceability and comparability, as prescribed by the World Meteorological Organization Global Cryosphere Watch programme.

永冻土退化是气候变化带来的日益严重的直接影响。从延伸、深度减少和活动层转移等方面检测永久冻土的收缩，对于把握趋势的严重程度以及采取行动和发出警告至关重要。通过永久冻土的温度曲线，可以直接了解冻土层的状况及其随时间的演变。Sommeiller Pass 永久冻土监测站海拔约 3000 米，是 2009 年欧洲 "PermaNET "项目在皮埃蒙特阿尔卑斯山（意大利西北部）建立的区域网络的主要站点。该站由三个不同特性的垂直钻孔组成，共配备 36 个热敏电阻，分布在三个不同的链条上。收集到的原始数据显示，自 2014 年以来，约 60 米深的永久冻土层基底出现退化，相当于每年约 0.03 °C。为了验证并更好地量化这种潜在的退化，进行了三次现场传感器校准活动，以了解这些测量的可靠性。通过在不同年份重复校准，取得了两项重要成果：校正了剖面误差，重新校准可区分多年来永久冻土温度的有效变化与传感器可能发生的漂移，后者可能与调查的热变化量级相同。深度为 60 米的冻土层基底变暖已得到证实，变暖速度为 (4.2 ± 0.5)∙10-2 °C/年。本文报告了现场计量实验室的实施和安装情况、采用的专用校准程序、校准结果和由此产生的调整数据、剖面及其随时间的变化情况。本文旨在为正在进行的最佳做法研究和定义做出进一步贡献，以便按照世界气象组织全球冰冻圈观察计划的规定，提高数据的可追溯性和可比性。

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引用次数: 0

A generalized thermal conductivity model of soil-rock mixture based on freezing characteristic curve 基于冻结特性曲线的土岩混合物广义导热模型

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-10 DOI: 10.1016/j.coldregions.2024.104360

Yindong Wang , Jianguo Lu , Wansheng Pei , Xusheng Wan , Jiajia Gao , Fei Deng

Soil-rock mixtures, served as important geotechnical materials for road construction and embankment dams, are widely distributed in cold regions. Thermal conductivity is a significant parameter in qualitatively assessing the heat transfer properties and determining the temperature field in cold regions geotechnical engineering. This study experimentally investigated the influence of rock content and temperature variations on the thermal conductivity of soil-rock mixtures, and a generalized thermal conductivity model based on the freezing characteristic curve was established. The results showed that both rock content and water-ice phase transitions affect the heat flux within soil-rock mixtures. The heat flux exhibited distinct variation trends during the freezing-thawing processes. Notably, hysteresis in heat flux was observed during the early stages of freeze-thaw cycles, disappearing after 8, 6, and 4 freeze-thaw cycles for soil-rock mixtures with rock contents of 10 %, 25 %, and 40 %, respectively. Additionally, the rock content seldom influenced the freezing temperature, while it significantly affected the thermal conductivity of soil-rock mixture. Furthermore, a generalized thermal conductivity model based on the freezing characteristic curve was established and verified, the proportion of thermal conductivity associated with the water-ice phase increased for the modified parallel model, while the modified series thermal conductivity model exhibited reversed results as the temperature decreased. Moreover, all the thermal conductivity models could obviously reflect the water-ice phase transition on the thermal conductivity of soil-rock mixture. However, the modified effective thermal conductivity model agreed best with the experimented results.

土岩混合物是筑路和堤坝的重要土工材料，广泛分布于寒冷地区。导热系数是寒冷地区岩土工程中定性评估传热性能和确定温度场的重要参数。本研究通过实验研究了岩石含量和温度变化对土岩混合物导热系数的影响，并建立了基于冻结特性曲线的广义导热系数模型。结果表明，岩石含量和水冰相变都会影响土岩混合物内部的热通量。在冻融过程中，热通量呈现出明显的变化趋势。值得注意的是，在冻融循环的早期阶段观察到了热通量的滞后现象，岩石含量为 10%、25% 和 40% 的土岩混合物分别在 8、6 和 4 个冻融循环后消失。此外，岩石含量很少影响冻结温度，但却对土岩混合物的导热性有很大影响。此外，还建立了基于冻结特性曲线的广义导热模型并进行了验证，修正的平行导热模型中与水冰相相关的导热比例增加，而修正的串联导热模型则随着温度的降低呈现相反的结果。此外，所有导热模型都能明显反映水冰相变对土石混合物导热系数的影响。然而，修正的有效导热模型与实验结果最为吻合。

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引用次数: 0

Freezing of a Supercooled Water Drop after an Impact onto a Solid Wall 过冷水滴撞击实心墙壁后冻结

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-09 DOI: 10.1016/j.coldregions.2024.104359

Mingyue Ding, Jeanette Hussong, Ilia V. Roisman

Supercooled water freezes as a result of ice nucleation, propagation along the substrate of a thin ice layer and subsequent expansion of a mushy region of ice dendrites. In this experimental study, the impact, spreading and solidification of the drop are observed in a cold wind tunnel using a high-speed video system. The statistics of the nucleation times after a supercooled water drop impacts onto a dry solid substrate are analyzed. The experiments demonstrate that the rate of the ice nucleation is enhanced significantly by drop impact and continuously reduces over time. The nucleation rate increases with higher impact velocity and is enhanced by the substrate roughness. This effect is explained by the presence of the small bubbles in the liquid drops, generated by drop impact and fast spreading. The surfaces of these bubbles serve as the additional triggers for ice nucleation. Moreover, the effect of the presence of the bubbles becomes even more significant when the wetted area reduces due to the drop receding. The average number of the nucleation sites in this case increases, since the number of bubbles does not reduce despite the reductions of the wetted area. These bubbles are probably captured by the receding contact line.

过冷的水结冰是由于冰核形成、薄冰层沿基底传播以及随后冰枝状突起的粘稠区域扩张。在这项实验研究中，使用高速视频系统在冷风隧道中观察了水滴的冲击、扩散和凝固过程。研究分析了过冷水滴撞击干燥固体基底后的成核时间统计。实验结果表明，水滴撞击会显著提高冰的成核率，并随着时间的推移不断降低。成核率随冲击速度的增加而增加，并因基底粗糙度而增强。液滴撞击和快速扩散产生的小气泡可以解释这种效应。这些气泡的表面是冰核形成的额外触发器。此外，当液滴后退导致润湿面积减小时，气泡存在的影响会变得更加显著。在这种情况下，成核点的平均数量会增加，因为尽管润湿面积减小，气泡的数量并没有减少。这些气泡可能被后退的接触线捕获。

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引用次数: 0

Exploring heat transfer in freezing supercooled water droplet through high-speed infrared thermography 通过高速红外热成像探索冻结过冷水滴中的热传递

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-07 DOI: 10.1016/j.coldregions.2024.104358

Hassan Abbas Khawaja , Samaneh Keshavarzi , Adeel Yousuf , Manaf Muhammed , Muhammad Shakeel Virk , Derek Harvey , Gelareh Momen

This study explores the intricate heat transfer dynamics and thermographic patterns during the phase change from supercooled liquid water to ice. Using high-resolution, high-speed infrared thermography, real-time temperature data were captured during the freezing process. The resulting temperature profiles reveal critical insights into the freezing dynamics, particularly highlighting the rapid phenomena of recalescence in supercooled conditions. Notably, this study represents the first time recalescence, a rapid and previously elusive phenomenon, captured and documented in the scientific literature. Additionally, a mathematical model is developed to describe the recalescence phase on macro scale. These findings have practical relevance for various industries, aiding in the design of more efficient anti−/de-icing technologies, refrigeration systems, weather prediction models, and cryopreservation techniques. The study also opens new avenues for further exploration in understanding phase transitions in supercooled water.

这项研究探索了从过冷液态水到冰的相变过程中错综复杂的传热动力学和热成像模式。利用高分辨率、高速红外热成像技术，在冷冻过程中采集了实时温度数据。由此获得的温度曲线揭示了冷冻动力学的重要见解，尤其突出了过冷条件下的快速再凝聚现象。值得注意的是，这项研究首次在科学文献中捕捉和记录了再凝聚这一以前难以捉摸的快速现象。此外，还建立了一个数学模型来描述宏观尺度上的再凝聚阶段。这些发现对各行各业都有实际意义，有助于设计更高效的防冰/除冰技术、制冷系统、天气预测模型和低温保存技术。这项研究还为进一步探索了解过冷水的相变开辟了新途径。

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引用次数: 0

Hydro-thermal processes and deformation of highway embankment in the active layer in a high-latitude permafrost region of Inner Mongolia in Northeast China 中国东北内蒙古高纬度冻土区活动层公路路堤的水热过程与变形

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-03 DOI: 10.1016/j.coldregions.2024.104357

Chunlei Xie , Yaqian Dong , Ze Zhang , Xianglong Li , Andrei Zhang , Doudou Jin

Construction of embankments in the permafrost region significantly changes the heat exchange conditions and hydrothermal transport processes between permafrost and the external environment, causing changes in the state of permafrost under the embankment, which in turn affects the long-term stability of embankment impacts. Considering more complex forest environment and higher technical standard for expressway than ordinary highway, the hydrothermal and deformation characteristics of the embankment are investigated through a full-scale field experimental embankment of the Genhe-Labdalin highway. Further, the study delves into the influence of changes in the active layer thickness, hydrothermal processes, and water above the frozen layer on embankment stability. The main conclusions are as follows: 1) The permafrost table, temperature, moisture and deformation of the embankment showed lateral heterogeneity, with the three-former showing a “concave shape” and the left side (sunny slope) being lower than the right side (shady slope). 2) The permafrost table appears to be unconnected (thawing interlayer), creating preferential flow, thaw zones and even through-thaw zones. 3) Accompanied by the freezing and thawing process of the embankment, the deformation of the pavement is less delayed. These findings will be helpful for better understanding the hydrothermal characteristics of embankments in different frozen ground regions, and for providing important technical guidance to ensure the safe operation of engineering projects.

在冻土区修建路堤会显著改变冻土与外界环境的热交换条件和水热输运过程，引起路堤下冻土状态的变化，进而影响路堤的长期稳定性。考虑到比普通公路更复杂的森林环境和高速公路更高的技术标准，本研究通过根河至拉布大林高速公路的全尺寸野外试验路堤，研究了路堤的水热和变形特性。此外，研究还深入探讨了活动层厚度变化、水热过程和冻结层上方的水对路堤稳定性的影响。主要结论如下1) 堤坝的冻土层、温度、湿度和变形呈现横向异质性，三变形体呈 "凹形"，左侧（阳坡）低于右侧（阴坡）。2) 多年冻土表层似乎互不相连（解冻夹层），形成了优先流、解冻区甚至贯通解冻区。3) 伴随路堤的冻融过程，路面的变形延迟较小。这些研究结果将有助于更好地了解不同冻土地区路堤的水热特性，为确保工程项目的安全运行提供重要的技术指导。

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引用次数: 0

Investigation of coupled thermo-hydro-mechanical processes on soil slopes in seasonally frozen regions 季节性冰冻地区土坡热-水-机械耦合过程研究

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-03 DOI: 10.1016/j.coldregions.2024.104356

Qimin Chen , Yong Liu , Yang Wang , Libin Su , Yonggang Cheng

Freeze-thaw cycles significantly affect slope stability in seasonally frozen regions, posing serious threats to the functionality and safety of infrastructure. This study developed a coupled thermo-hydro-mechanical (THM) model of frozen soils that accounts for water migration, water-ice phase change, groundwater recharge, frost heave and thaw settlement deformation. The accuracy and reliability of the model was verified based on soil column test results. The change of temperature, water content, and displacement of a soil slope during freeze-thaw process was investigated. The results show that the water-heat transfer and deformation mainly occur in the shallow soils of the slope with changes in air temperature. The temperature fluctuations at the shoulder and face of the slope are more pronounced than those at the toe and crest of the slope. Water migration from the unfrozen zone to the freezing front due to the temperature gradient results in an increase in water content in the frozen zone. The slope shoulder exhibits the largest temperature fluctuations, leading to increased water migration and greater deformation. The rising groundwater table increases the total water content at the slope toe and base, exacerbating the frost heave and thaw settlement deformation, and reasonable groundwater table control intervals are provided. This study elucidates the thermo-hydro-mechanical coupling process and deformation mechanism of seasonally frozen soil slopes, and summarizes the failure modes, which provides a reference for the stability assessment and disaster prevention of soil slopes in cold regions.

冻融循环严重影响季节性冰冻地区的边坡稳定性，对基础设施的功能和安全构成严重威胁。本研究开发了冻土的热-水-力学（THM）耦合模型，该模型考虑了水迁移、水冰相变、地下水补给、冻胀和融冻沉降变形。该模型的准确性和可靠性已根据土柱测试结果得到验证。研究了冻融过程中土坡温度、含水量和位移的变化。结果表明，随着气温的变化，水热传递和变形主要发生在边坡浅层土壤中。坡肩和坡面的温度波动比坡脚和坡顶更为明显。由于温度梯度，水从未冻区向冻结前沿迁移，导致冻结区含水量增加。坡肩的温度波动最大，导致水迁移增加，变形加大。地下水位的上升增加了坡脚和坡底的总含水量，加剧了冻胀和融冻沉降变形，并提供了合理的地下水位控制区间。该研究阐明了季节性冻土边坡的热-水-机械耦合过程和变形机理，总结了其破坏模式，为寒冷地区土质边坡的稳定性评估和灾害防治提供了参考。

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引用次数: 0

Comparative study of thaw settlement susceptibility mapping for the Qinghai-Tibet Plateau based on index and machine learning models 基于指数和机器学习模型的青藏高原冻融沉降易感性绘图比较研究

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.coldregions.2024.104354

Renwei Li , Mingyi Zhang , Wansheng Pei , Zhao Duan , Haitao Jin , Xin Li

Climate warming has caused frequent thaw settlement in the permafrost region of the Qinghai-Tibet Plateau (QTP), significantly threatening the ecological environment and infrastructure. This study assesses thaw settlement susceptibility using index and machine learning (ML) models and compares their accuracies. The settlement index (Is), risk zonation index (Ir), and geohazard index (Ia) models were selected to map thaw settlement susceptibility, and their results were combined to construct a comprehensive index (Ic) model using a majority vote criterion. Based on 12 conditioning factors related to topography, soil, vegetation, and climate, susceptibility studies using artificial neural network (ANN), K-nearest neighbor (KNN), support vector machine (SVM), and random forest (RF) models were conducted. The results indicate that although the Ic model improves the accuracies of the Is, Ir and Ia models, it remains limited, with 75.06% of thaw settlements occurring in low and moderate susceptibility areas. Conversely, the ML models demonstrated superior accuracy, with the RF model performing the best, which remained only 13.87% of thaw settlements in low to moderate susceptibility regions, effectively pinpointing the Qiangtang Plateau (QP) and Three Rivers Source (TRS) region as high susceptibility areas. Notably, the Budongquan-Beiluhe sections of the Qinghai-Tibet Highway (QTH) and Qinghai-Tibet Railway (QTR) were identified as potential high-risk regions for thaw settlement. These findings offer valuable insights for thaw settlement susceptibility evaluation and disaster risk management in the QTP.

气候变暖导致青藏高原（QTP）冻土区频繁出现融冻沉降，严重威胁生态环境和基础设施。本研究采用指数和机器学习（ML）模型对融冻沉降敏感性进行评估，并比较其准确性。研究选取了沉降指数（Is）、风险分区指数（Ir）和地质灾害指数（Ia）模型来绘制解冻沉降易感性图，并采用多数票标准将它们的结果组合起来构建综合指数（Ic）模型。根据与地形、土壤、植被和气候相关的 12 个条件因子，使用人工神经网络 (ANN)、K-近邻 (KNN)、支持向量机 (SVM) 和随机森林 (RF) 模型进行了易感性研究。结果表明，虽然 Ic 模型提高了 Is、Ir 和 Ia 模型的精确度，但仍有局限性，75.06% 的解冻沉降发生在低度和中度易感地区。相反，ML 模型则表现出更高的准确性，其中 RF 模型表现最佳，仅有 13.87% 的融冻沉降发生在中低易感地区，有效地将羌塘高原和三江源地区定位为高易感地区。值得注意的是，青藏公路（QTH）和青藏铁路（QTR）的布东泉至北路河段被确定为潜在的融雪沉降高风险区。这些发现为青藏高原地区的融冻沉降易感性评估和灾害风险管理提供了宝贵的启示。

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引用次数: 0

Relationship of physical and mechanical properties of sea ice during the freeze-up season in Nansen Basin 南森盆地冻结期海冰物理和机械特性的关系

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.coldregions.2024.104353

Vegard Hornnes , Evgenii Salganik , Knut Vilhelm Høyland

Sea-ice properties, such as porosity and strength, can have significant spatial variability at small scales. Quantifying this variability may give better estimates of the ice properties and their interrelation. Additionally, correlating in situ ice strength measurements and ice properties, including porosity, may improve understanding of the factors influencing ice strength. This paper presents measurements of sea-ice properties and strength on first- and second-year sea ice during the GoNorth expedition to the Arctic Ocean in October 2022. In situ borehole indentation measurements were co-located with measurements of physical properties, and the meter-scale variability of the physical properties and strength was investigated. Bulk density values found from hydrostatic weighing were 911 ± 5 kg m⁻³ for first-year and 904 ± 5 kg m⁻³ for second-year ice, with significantly less uncertainty than density values from the mass/volume method or from freeboard/draft measurements. The second-year ice was relatively saline, with a mean bulk salinity of 3.1 ± 0.5, and the ice was desalinated in the upper and lower 0.2 m. The bulk gas fraction in the second-year ice was 2.5 ± 0.5 %, similar to the first-year ice gas fraction of 2.8 ± 0.5 %. Gas fractions up to 6.5 % were observed in the second-year ice without any obvious correlation with the brine fraction. The second-year ice had larger spatial variability in thickness, porosity, grain structure, and ice strength compared to the first-year ice. Variability in bulk density and gas fraction were similar for first- and second-year ice, as the larger variability was mostly seen below the upper 0.4 m of the second-year ice. The borehole strength was 26.0 ± 4.4 MPa for first-year and 41.0 ± 12.1 MPa for second-year ice. There were indications that the total microporosity at indentation depth was related to in situ borehole strength (

R^{2}

= 0.82), and that brine volume was the most influential parameter. The relative variability in the local microporosity in the second-year ice (0.43) was greater than the relative variability in borehole strength (0.27), while the opposite was true for the first-year ice (0.09 versus 0.17).

海冰特性，如孔隙度和强度，在小尺度上会有很大的空间变化。量化这种变异性可以更好地估计冰的特性及其相互关系。此外，将原位冰强度测量结果与包括孔隙度在内的冰属性联系起来，可以加深对影响冰强度的因素的理解。本文介绍了 2022 年 10 月在北冰洋 GoNorth 考察期间对第一年和第二年海冰的特性和强度进行的测量。现场钻孔压痕测量与物理性质测量同时进行，并对物理性质和强度的米级变化进行了研究。通过静力学称重发现，第一年冰的体积密度值为 911 ± 5 kg m-3，第二年冰的体积密度值为 904 ± 5 kg m-3，其不确定性明显小于质量/体积法或自由板/透气度测量法得出的密度值。第二年冰的盐度相对较高，平均体积盐度为 3.1 ± 0.5，冰的上部和下部 0.2 米处脱盐。在第二年冰层中观测到的气体分数高达 6.5%，但与盐水分数没有明显的相关性。与第一年冰相比，第二年冰在厚度、孔隙度、晶粒结构和冰强度方面的空间变化较大。第一年和第二年冰的容积密度和气体组分的变异性相似，因为较大的变异性主要出现在第二年冰的上层 0.4 米以下。第一年冰的钻孔强度为 26.0 ± 4.4 兆帕，第二年冰的钻孔强度为 41.0 ± 12.1 兆帕。有迹象表明，压痕深度的总微孔与现场钻孔强度有关（R2 = 0.82），而盐水体积是影响最大的参数。二年冰局部微孔的相对变异性（0.43）大于钻孔强度的相对变异性（0.27），而一年冰的情况正好相反（0.09 对 0.17）。

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引用次数: 0

Prototype observation and analysis of static ice pressure on reservoir piers in cold regions 寒冷地区水库码头静冰压力的原型观测与分析

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.coldregions.2024.104352

Wenliang Qiu , Kuan Li , Xin Zhao , Zhaolong Hou , Zhenguo Wang , Junpeng Yu

Static ice pressure is an important factor threatening the structural safety of bridges built in cold region reservoirs. Bridge piers will be subjected to high static ice pressure during the conversion of water to ice, which may cause deformation or even failure of piers. To investigate the spatial and temporal distribution of static ice pressure, this study carried out a two-year field observation experiment on the ice sheet of the Xilamulun Reservoir in Inner Monggol, China. A novel ice pressure panel was designed to measure static ice pressure in this work. Meanwhile, the air temperature, ice temperature, and ice thickness were recorded to analyze the influencing factors of static ice pressure. The results show that the new ice pressure panel provided an accurate measurement of the varying ice pressure and its vertical distribution within the ice sheet. The ice thickness growth factor was calculated based on the Freezing Ice Degree Day model, and snowfall was the critical parameter affecting the ice thickness growth factor. The new formulas for calculating the temperature distribution within the ice sheet were presented, in which critical parameters were determined based on measured data. The calculated ice pressures matched well with the observed values, which indicates the validity of the presented formulas. The maximum ice pressure on piers occurred at 1/3 to 1/2 of the ice thickness below the ice surface and gradually moved downward as the ice thickness increased. Moreover, the ice pressure is not only affected by the air temperature but also by the cracking state of the ice sheet, constraints, sunshine time, etc. This study can be used to predict ice sheet growth, ice pressure, and ice temperature distribution and contribute to the ice-resistant design of bridge piers in cold region reservoirs.

静冰压力是威胁寒冷地区水库桥梁结构安全的一个重要因素。桥墩在水冰转换过程中会承受较高的静冰压力，可能导致桥墩变形甚至失效。为了研究静冰压力的时空分布，本研究在中国内蒙古锡林郭勒盟西拉木伦水库的冰层上进行了为期两年的野外观测实验。本研究设计了一种新型冰压板来测量静态冰压。同时，记录了气温、冰温和冰厚，分析了静态冰压的影响因素。结果表明，新型冰压板可准确测量冰层内的变化冰压及其垂直分布。冰层厚度增长因子是根据冻冰度日模型计算得出的，降雪量是影响冰层厚度增长因子的关键参数。提出了计算冰原内部温度分布的新公式，其中关键参数是根据测量数据确定的。计算得出的冰压力与观测值非常吻合，这表明所提出的公式是正确的。桥墩上的最大冰压力出现在冰面以下 1/3 至 1/2 的冰厚度处，并随着冰厚度的增加逐渐向下移动。此外，冰压不仅受气温影响，还受冰层开裂状态、制约因素、日照时间等因素的影响。这项研究可用于预测冰层生长、冰压和冰温分布，有助于寒冷地区水库桥墩的抗冰设计。

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