scholarly journals Application of the Generalized Clapeyron Equation to Freezing Point Depression and Unfrozen Water Content

2018 ◽  
Vol 54 (11) ◽  
pp. 9412-9431 ◽  
Author(s):  
Jiazuo Zhou ◽  
Changfu Wei ◽  
Yuanming Lai ◽  
Houzhen Wei ◽  
Huihui Tian
Keyword(s):  
Water Content ◽  
Freezing Point ◽  
Unfrozen Water ◽  
Freezing Point Depression ◽  
Clapeyron Equation ◽  
Unfrozen Water Content

scholarly journals Variation features of unfrozen water content of water-saturated coal under low freezing temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bo Li ◽  
Laisheng Huang ◽  
Xiaoquan Lv ◽  
Yongjie Ren
Keyword(s):  
Water Content ◽  
Pore Water ◽  
Pore Radius ◽  
Freezing Point ◽  
Melting Process ◽  
Freezing Process ◽  
Unfrozen Water ◽  
Hysteresis Phenomenon ◽  
Unfrozen Water Content ◽  
Water Saturated

AbstractTo determine the unfrozen water content variation characteristics of coal from the low temperature freezing based on the good linear relationship between the amplitude of the nuclear magnetic resonance (NMR) signal and movable water, pulsed NMR technology was used to test water-saturated coal samples and analyze the relationship between the unfrozen water content, the temperature and pore pressure during freeze–thaw from a microscopic perspective. Experimental results show that the swelling stress of the ice destroys the original pore structure during the freezing process, causing the melting point of the pore ice to change, so the unfrozen water content during the melting process presents a hysteresis phenomenon. When phase equilibrium has been established in the freezing process, the unfrozen water is mainly the film water on the pore surface and pore water in pores with pore radius below 10 nm. At this time, the freezing point of the water in the system decreases exponentially as the temperature increases. The micropores of the coal samples from the Jiulishan Coalmine are well-developed, and the macropores and fractures are relatively small, with most pores having a pore radius between 0.1 and 10 nm. The pore water freezing point gradually decreases with the pore radius. When the pore radius decreases to 10 nm, the freezing point of pore water starts to decrease sharply with the decreasing pore radius. When the pore radius reaches 1.54 nm, the pore water freezing point changes as fast as 600 ℃/nm.

A method for calculating unfrozen water content of silty clay with consideration of freezing point

2018 ◽  
Vol 161 ◽  
pp. 474-481 ◽  
Author(s):  
Mingtang Chai ◽  
Jianming Zhang ◽  
Hu Zhang ◽  
Yanhu Mu ◽  
Gaochen Sun ◽  
...  
Keyword(s):  
Water Content ◽  
Freezing Point ◽  
Unfrozen Water ◽  
Silty Clay ◽  
Unfrozen Water Content

scholarly journals Electrical Conductivity-Based Estimation of Unfrozen Water Content in Saturated Saline Frozen Sand

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zejin Lai ◽  
Xiaodong Zhao ◽  
Rui Tang ◽  
Jinhong Yang
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Water Content ◽  
Freezing Point ◽  
Salt Content ◽  
Free Water ◽  
Conductivity Measurement ◽  
Unfrozen Water ◽  
Essential Difference ◽  
Unfrozen Water Content

The salinity of the pore solution is closely associated with the unfrozen water content and can be reflected by variation in electrical conductivity in frozen soils. However, the influence of salinity was not considered in the existing models for estimation of unfrozen water content based on electrical conductivity measurement, and a model considering the effect of salt content was therefore developed to estimate the change of unfrozen water content of saline sands with variation of salt content (0%, 0.2%, and 1%). The unfrozen water content and the electrical resistivity were measured by nuclear magnetic resonance (NRM) and using resistance test equipment under a temperature ranging from 25°C to −15°C, respectively. The results indicated that the model using a cementation exponent expressed by a piecewise function with respect to temperature can produce a reasonable estimation on the content of unfrozen water. There was an essential difference between nonsaline and saline frozen sands in the increase of electrical resistivity due to the different reduction rates of unfrozen water content. The variation of electrical resistivity in nonsaline sand was mainly caused by the decrease of free water when temperature was higher than the freezing point and adsorbed water when temperature was lower than the freezing point, whereas the reduction of free water in two stages was the main reason for the variation of electrical resistivity in saline sand. The results and data obtained provided a basis for further developing a novel approach to measure the unfrozen water content in the field.

Predicting Unfrozen Water Contents in Frozen Soils

1966 ◽  
Vol 3 (2) ◽  
pp. 53-60 ◽  
Author(s):  
Howard B Dillon ◽  
O B Andersland
Keyword(s):  
Water Content ◽  
Freezing Point ◽  
Soil Mechanics ◽  
Frozen Soil ◽  
Unfrozen Water ◽  
Silty Clay ◽  
Frozen Soils ◽  
Unfrozen Water Content ◽  
Experimental Values ◽  
Water Contents

A relationship between temperature and certain soil properties including specific surface area, activity ratio, and the expandable clay lattice, is presented for predicting the unfrozen water content of frozen soils. Data on experimental calorimetric determinations for ice content of two frozen clays and a frozen silty clay are given. Predicted unfrozen water contents are compared with experimental values for eleven soils with good agreement in all cases. Temperatures close to and above the freezing point depression of the soil are excluded. Knowledge of the unfrozen water content in frozen soils permits a more realistic approach to a variety of problems in frozen soil mechanics.

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