Cold Regions Science and Technology最新文献

Numerical study on cooling performance of the L-shaped crushed-rock embankment in permafrost regions

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-26 DOI: 10.1016/j.coldregions.2024.104380

Yafang Guo , Wansheng Pei , Mingyi Zhang , Deren Liu , Ruiqiang Bai , Yanqiao Zhou , Guanji Li

In permafrost regions, crushed-rock embankments are favored for their environmental compatibility and thermal efficiency. This study introduces the innovative L-shaped crushed-rock embankment (LCRE), which features a crushed-rock layer exclusively at the base and on the sunny slope, providing a cost-effective alternative to the conventional U-shaped design. Using numerical methods, we assessed the cooling performance of the LCRE compared to other crushed-rock embankments, focusing on the impact of its geometric parameters. The findings indicate that the overall cooling performance of the LCRE is situated between that of the crushed-rock interlayer embankment and the U-shaped crushed-rock embankment, and its ability to mitigate the shady and sunny slope effect is superior to that of the U-shaped crushed-rock embankment. Additionally, our analysis reveals that increasing the horizontal width of the revetment to enhance cooling is not a cost-effective approach. The LCREs is more suitable for higher embankments than U-shaped counterparts. Despite the LCRE's advantageous thermal performance and cost benefits, its asymmetric load distribution could lead to exacerbated differential settlement, highlighting the need for further research. This study offers pivotal insights into the design and development of innovative crushed-rock embankments in permafrost regions.

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引用次数: 0

Who skis where, when? – A method to enumerate backcountry usage 谁在何时何地滑雪？- 列举越野滑雪使用情况的方法

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-22 DOI: 10.1016/j.coldregions.2024.104370

Håvard B. Toft , Kristoffer Karlsen , Markus Landrø , Andrea Mannberg , Jordy Hendrikx , Audun Hetland

Backcountry skiers, travelling in avalanche terrain, account for a large proportion of avalanche fatalities worldwide. Despite this, the exact count of the number of recreationists exposed to avalanches (also known as the background information), is poorly documented in most countries. Without detailed background information on temporal and spatial backcountry usage, making well-reasoned decisions from fatality statistics is impossible. This study developed a methodology to enumerate a large proportion of backcountry usage from a 2589 km² study area in Tromsø, Northern Norway. We use an extensive network of specially adapted beacon checkers – small, waterproof devices that detect and count signals from avalanche transceivers. Over two seasons, from December to May from 2021 to 2023, we recorded 56,760 individual trips. Our findings indicate that most (60.0 %) backcountry trips begin between 07:00 and 12:00, with noticeable activity in the afternoon as well. Saturdays and Sundays see the highest daily activity rates, comprising 40.1 % of total weekly traffic, while weekdays, though less busy per day, account for the remaining 59.9 %. The peak season for winter backcountry skiing is during March and April (when counts from the period December to May are considered), accounting for 56.3 % of all traffic. This monthly usage aligns with avalanche incident data, where 55.8 % of incidents occur during the same two months. Our study demonstrates the use of our methodology and advances the understanding of temporal trends from winter backcountry skiing, quantifying the movement characteristics of backcountry skiers in Tromsø, Norway.

在雪崩地带旅行的越野滑雪者在全球雪崩死亡人数中占很大比例。尽管如此，大多数国家对暴露于雪崩的娱乐者人数的确切统计（也称为背景信息）却很少记录。如果没有关于野外使用的时间和空间的详细背景信息，就不可能根据死亡统计数据做出合理的决策。这项研究开发了一种方法，可以从挪威北部特罗姆瑟 2589 平方公里的研究区域中统计出很大一部分野外活动的使用情况。我们使用了一个由经过特别改装的信标检查器组成的广泛网络--这种小型防水设备可以检测和统计雪崩收发器发出的信号。在2021年至2023年的12月至5月的两个季节里，我们记录了56,760次单次雪崩。我们的研究结果表明，大多数（60.0%）越野旅行开始于 7:00 至 12:00，下午也有明显的活动。周六和周日的日活动率最高，占每周总流量的 40.1%，而工作日虽然每天的活动量较少，但也占其余 59.9%。冬季越野滑雪的旺季在 3 月和 4 月（考虑到 12 月至 5 月期间的统计数字），占总流量的 56.3%。每月的使用情况与雪崩事故数据一致，55.8% 的事故发生在这两个月。我们的研究展示了我们的方法的使用，并推进了对冬季越野滑雪时间趋势的理解，量化了挪威特罗姆瑟越野滑雪者的运动特征。

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引用次数: 0

Unified hardening (UH) model for saturated frozen soils

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-20 DOI: 10.1016/j.coldregions.2024.104371

Kesong Tang, Yangping Yao

The mechanical behavior of frozen soils is highly sensitive to temperature variations due to their complex micro-mechanisms. In regions with seasonal freeze-thaw cycles, the transition of soils between frozen and unfrozen states is significantly influencing their mechanical properties. This study synthesizes existing theories and data to categorize the effects of subzero temperatures on the properties of frozen soils. By introducing temperature and unfrozen water saturation, the phase change component of void ratio—decoupled from stress—is distinguished from actual voids, enabling the definition of the equivalent void ratio. Nonlinear relationships between temperature and other mechanical properties including elastoplastic deformation, cryogenic cohesion and ice segregation are established. Through the derivation of a loading-temperature yield equation, an elastoplastic constitutive model within a dual stress-variable framework of effective stress and temperature is established. This model captures key aspects of the behavior of frozen soils, including strength weakening due to ice segregation and temperature-induced strength changes. Applicable to conditions at or below the pore water melting point, the model's predictions align well with experimental observations.

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引用次数: 0

Influence mechanism of AC electric field on rime ice accretion on the insulator and its experimental verification in the natural environment

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-19 DOI: 10.1016/j.coldregions.2024.104367

Mingchen Chi , Yuyao Hu , Xingliang Jiang , Zongyuan Liu , Yue Gao , Mengyang Zhao , Wentao Jia

Insulator icing can easily trigger flashover trips in heavily ice-covered areas, and analyzing the formation mechanism of ice accumulation on the insulator is essential for predicting its flashover development. To accurately dissect the process of insulator icing, a coupled mathematical model of the flow field and electric field, as well as a droplet motion model were elaborated in this paper based on the principles of fluid mechanics and electromagnetic field. Subsequently, the characteristics of droplet motion deviation and its physical collision process with an insulator surface under AC electric field were investigated. The results demonstrate that the charged droplets tend to oscillate along the electric field lines in AC electric field, and the amplitude of the oscillation increases with the applied voltage increasing. Moreover, the number of droplets captured by the insulator rises with the increase of voltage, wind speed, and median volume diameter of the droplet. Combined with the simulation and natural icing experiments, it is observed that ice branches grow in the direction of electric field force, and as the voltage rises, ice branches gradually spread from the edge of the shed to its surface, increasing surface roughness. The density of ice exhibits an inverted U-shaped relationship as the electric field strength increases. Ice mass and ice length present nonlinear growth with an increase in icing time. Furthermore, compared with that without energization, the icing amount and icing length increase by more than 13 % under AC voltage of 40 kV.

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引用次数: 0

The theoretical freezing model of sandstone considering the statistical arrangement of pore structure 考虑孔隙结构统计排列的砂岩理论冻结模型

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-17 DOI: 10.1016/j.coldregions.2024.104366

Hui Zhang , Yugui Yang , Chengzheng Cai , Shanshan Hou , Chenxiang Li

It is of great significance to understand the evolution law of unfrozen water content in frozen rocks to maintain the stability of geotechnical engineering in cold regions. Due to the different particle sizes and shapes, coupled with the diversity of cements, the internal pore structures of rocks are complex and diverse. In this study, a theoretical model for freezing point of sandstone is proposed based on the characteristics of microscopic pore structures. The characteristic of freezing point is analyzed by considering the mineral particle arrangement. A statistical theoretical model of unfrozen water in sandstone is established according to the random arrangement of mineral particles. The influence of the stacking angle of mineral particles following the normal distribution on unfrozen water content is analyzed. Finally, the NMR freezing process analysis for sandstones was carried out. The results show that the statistical theoretical model of unfrozen water fits the experimental results well. The effect of the average value of stacking angle on unfrozen water content is mainly due to the change of pore size, which leads to the change of pore water content. The standard deviation of stacking angle determines the residual water content.

了解冻结岩石中未冻结含水量的演变规律，对于保持寒冷地区岩土工程的稳定性具有重要意义。由于岩石的颗粒大小和形状不同，再加上胶结物的多样性，岩石内部孔隙结构复杂多样。本研究根据微观孔隙结构的特点，提出了砂岩凝固点的理论模型。通过考虑矿物颗粒的排列来分析凝固点的特征。根据矿物颗粒的随机排列，建立了砂岩中未冻结水的统计理论模型。分析了服从正态分布的矿物颗粒堆积角对解冻水含量的影响。最后，对砂岩进行了核磁共振冷冻过程分析。结果表明，解冻水的统计理论模型很好地拟合了实验结果。堆积角平均值对解冻含水量的影响主要是由于孔隙大小的变化导致孔隙含水量的变化。堆积角的标准偏差决定了残余含水量。

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引用次数: 0

Experimental investigation of cyclic responses of frozen soil under principal stress rotation induced by wave loads 波浪荷载诱发主应力旋转下冻土循环响应的实验研究

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-17 DOI: 10.1016/j.coldregions.2024.104368

Furong Liu , Wei Ma , Zhiwei Zhou , Zhi Wen , Mingde Shen , Ruiqiang Bai

Under the effect of wave loads, continuous and cyclic principal stress rotation (PSR) occurs, with constant principal stress values in foundation soil units. The stability of coastal engineering structures in permafrost regions is inevitably subjected to the persistent impact of wave loads, which poses a significant challenge to their durability. Consequently, a series of experimental studies were carried out using a frozen hollow cylinder apparatus (FHCA) to investigate the influence of crucial three-dimensional stress state parameters, including the coefficient of intermediate principal stress (b), mean principal stress (p), and principal stress rotation radius (R), on the deformation characteristics and dynamic property evolution of frozen soils. The results indicated that under continuous principal stress rotation, the mean principal stress p has a limited impact on the deformation behavior and mechanical property evolution of the frozen soil. In contrast, b and R significantly influence the mechanical properties of frozen soil. When b and R at low values, the continuous rotation of principal stress causes axial strain to develop positively, decreases the mechanical property parameter damping ratio, increases the elastic modulus, and densified the sample. However, with the increase in b and R beyond a threshold, the repeated principal stress rotation causes the axial strain to develop negatively, increases the damping ratio continuously, decreases elastic modulus, and leads to significant softening of the frozen soil with an increase in rotation cycles.

在波浪荷载的作用下，地基土单元的主应力值恒定，会发生持续和周期性的主应力旋转（PSR）。永冻土地区海岸工程结构的稳定性不可避免地受到波浪荷载的持续影响，这对其耐久性提出了重大挑战。因此，利用冻土空心圆柱体装置（FHCA）开展了一系列实验研究，探讨中间主应力系数（b）、平均主应力（p）和主应力旋转半径（R）等关键三维应力状态参数对冻土变形特征和动力特性演变的影响。结果表明，在连续主应力旋转条件下，平均主应力 p 对冻土的变形行为和力学性质演变影响有限。相比之下，b 和 R 对冻土的力学性质影响较大。当 b 和 R 值较低时，主应力的连续旋转会导致轴向应变正向发展，降低力学性能参数阻尼比，增加弹性模量，并使样品致密化。然而，随着 b 和 R 的增大超过临界值，反复的主应力旋转会导致轴向应变负增长，阻尼比持续增大，弹性模量减小，并随着旋转周期的增加导致冻土显著软化。

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引用次数: 0

Chemical composition and properties of Ski wax: A comprehensive analysis of fluorinated, non-fluorinated, and bio-based waxes Ski 蜡的化学成分和特性：含氟、无氟和生物蜡的综合分析

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-15 DOI: 10.1016/j.coldregions.2024.104365

Lorenz Cushman, Justin Zsiros, Gus Kaeding, Jeffrey Bates

This study analyzes the chemical composition and thermal properties of various ski wax materials, including fluorinated, non-fluorinated petroleum-based, and bio-based waxes. Advanced characterization techniques (FTIR, EDS, and DSC) were used to investigate the chemical functionality, elemental composition, and thermal behavior of these waxes. Fluorinated powder waxes were found to be composed almost entirely of fluorocarbons, while solid fluorinated waxes are primarily hydrocarbons with minimal fluorine content. Bio-based waxes exhibit unique ester and carboxylic acid functional groups. Different brands, models, and suggested temperature uses of waxes within the same physical and chemical type show similar chemical compositions. While petroleum-based compared to bio-based waxes show a significant difference in chemical structure. EDS analysis identified silicon, magnesium, and aluminum in certain waxes, possibly indicating the use of additives. DSC results showed similar thermal behavior at sub-freezing temperatures. This research lays the groundwork for understanding ski wax material science and opens up new avenues for future investigation and innovation in the ski and ski wax industry.

本研究分析了各种滑雪蜡材料的化学成分和热性能，包括含氟、非含氟石油基和生物基蜡。研究采用了先进的表征技术（傅立叶变换红外光谱、电致发光光谱和二氯甲烷）来研究这些蜡的化学功能、元素组成和热行为。研究发现，含氟粉末蜡几乎完全由碳氟化合物组成，而固体含氟蜡主要是碳氢化合物，氟含量极低。生物基蜡表现出独特的酯和羧酸官能团。在相同的物理和化学类型中，不同品牌、型号和建议温度下使用的蜡具有相似的化学成分。而石油蜡与生物蜡在化学结构上有显著差异。EDS 分析在某些蜡中发现了硅、镁和铝，这可能表明使用了添加剂。DSC 结果表明，在亚冰点温度下的热行为相似。这项研究为了解滑雪蜡材料科学奠定了基础，并为滑雪和滑雪蜡行业未来的研究和创新开辟了新途径。

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引用次数: 0

Damage mechanism and energy evolution of frozen soil under coupled compression–shear impact loading 压缩-剪切耦合冲击荷载下冻土的破坏机理和能量演化

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-14 DOI: 10.1016/j.coldregions.2024.104361

Zhiwu Zhu , Taiyu Zhang , Yanwei Wang , Yue Ma , Zhengqiang Cheng

In cold region engineering, the impact of coupled compression–shear loading on frozen soil foundations is a critical issue that urgently needs to be addressed, as it often significantly reduces bearing capacity and can cause structural failures. Accurately characterizing the mechanical behavior of frozen soil under dynamic coupled compression–shear loading is essential for enhancing the safety and stability of cold region engineering projects. This study prepared four frozen-soil specimens with varying tilting angles to investigate failure mechanisms and energy evolution under coupled compression–shear impact loading. The impact-compression experiments were conducted on the specimens under different loading strain rates and temperature conditions using a split Hopkinson pressure bar. The results indicated that the strength of frozen soil was effectively enhanced by higher strain rates and lower temperatures, while it was reduced by increased tilting angle. The fracturing morphology of frozen soil was analyzed from both microscopic and macroscopic perspectives to reveal its failure mechanisms. To quantify the strength characteristics of the frozen soil under various loading conditions, damage variables were defined from an energy-based perspective and incorporated into the Zhu–Wang–Tang viscoelastic constitutive model. Hence, a dynamic constitutive model for frozen soil under coupled compression–shear loading was developed. The model's predictive capability was validated through comparisons with the experimental data, which revealed a high level of agreement. The results of this study provide practical insights into the failure mechanisms and construction design of frozen soil foundations under coupled compression–shear impact loading in cold region engineering.

在寒冷地区工程中，压缩-剪切耦合载荷对冻土地基的影响是一个亟待解决的关键问题，因为它通常会显著降低承载能力，并可能导致结构失效。准确描述动态压缩剪切耦合荷载下冻土的力学行为对提高寒冷地区工程项目的安全性和稳定性至关重要。本研究制备了四个不同倾斜角度的冻土试样，以研究压缩-剪切耦合冲击荷载下的破坏机制和能量演化。在不同的加载应变速率和温度条件下，使用分体式霍普金森压力棒对试样进行了冲击压缩实验。结果表明，应变速率越高、温度越低，冻土的强度就越高，而倾斜角度越大，强度就越低。从微观和宏观角度分析了冻土的断裂形态，以揭示其破坏机制。为了量化冻土在各种加载条件下的强度特征，从基于能量的角度定义了破坏变量，并将其纳入朱-王-唐粘弹性构成模型。因此，开发出了压缩-剪切耦合加载下的冻土动力构成模型。该模型的预测能力通过与实验数据的比较得到了验证，结果表明两者具有很高的一致性。研究结果为寒冷地区工程中压缩-剪切耦合冲击荷载下冻土地基的破坏机理和施工设计提供了实用见解。

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引用次数: 0

Effects of increased rainfall on heat and mass transfer and deformation of sulfate saline soil: An experimental investigation 降雨量增加对硫酸盐盐碱土壤传热、传质和变形的影响：实验研究

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology

Pub Date : 2024-11-14 DOI: 10.1016/j.coldregions.2024.104363

Zhixiong Zhou , Fengxi Zhou , Mingli Zhang , Xusheng Wan , Liujun Zhang

To study the effect of increased rainfall on the heat and mass transfer and deformation characteristics of sulfate saline soil, a geometric similarity ratio model (1:6) of the natural site was created inside the self-developed indoor baseplate-atmospheric dual-temperature control model box. For the first time, combined with the characteristics of the surface energy change, the characteristics of water-heat-salt-mechanical coupling changes within sulfate saline soil under normal rainfall and twice the increase in rainfall were studied. The results show that the increased rainfall leads to a more significant decrease in upward shortwave radiation and downward longwave radiation, as well as a more significant increase in the surface net radiation and surface evaporation rate. Additionally, the increase in rainfall leads to an obvious cooling trend in the surface temperature. Compared with normal rainfall, an increase in rainfall leads to a significant increase in soil water content and conductivity, while soil heat flux and temperature significantly decrease. The increased rainfall caused a temperature drop of 1.6 °C at 5 cm of saline soil. Moreover, the increased rainfall leads to an increase in the heat release time of sulfate saline soil. Meanwhile, the impact of increased rainfall on the soil water content, conductivity, and temperature gradually weakens with increasing depth. The increased rainfall can exacerbate thawing settlement deformation and alleviate salt frost heave deformation. Compared with normal rainfall, twice the increase in rainfall results in a 0.9 mm increase in thawing settlement deformation and a 2.5 mm decrease in salt frost heave deformation.

为研究增雨对硫酸盐盐渍土传热传质及变形特性的影响，在自行研制的室内基板-大气双温控模型箱内建立了自然场地几何相似比模型（1:6）。首次结合地表能量变化特征，研究了正常降雨和两倍增雨条件下硫酸盐盐渍土内部水-热-盐-力学耦合变化特征。结果表明，降雨量增加会导致向上的短波辐射和向下的长波辐射有更明显的减少，地表净辐射和地表蒸发率也会有更明显的增加。此外，降雨量的增加还导致地表温度呈明显的下降趋势。与正常降雨量相比，降雨量增加导致土壤含水量和导电率显著增加，而土壤热通量和温度则明显下降。降雨量增加导致盐碱地 5 厘米处温度下降 1.6 °C。此外，降雨量的增加导致硫酸盐盐碱土的热量释放时间增加。同时，降雨增加对土壤含水量、电导率和温度的影响随着深度的增加而逐渐减弱。增加的降雨量会加剧解冻沉降变形，减轻盐霜隆起变形。与正常降雨量相比，增加一倍的降雨量会导致解冻沉降变形增加 0.9 毫米，盐霜波浪变形减少 2.5 毫米。

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引用次数: 0

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