Irreducible water saturation in snow: experimental results in a cold laboratory

The porosity of wet snow is often about 50%; however, liquid water generally fills less than 10% of this pore volume. In order to relate the irreducible water content trapped in snow to its characteristics, we have conducted experiments in a cold laboratory. The results show that irreducible water content, expressed as per cent of mass, depends only on porosity. Experimental studies were restricted to homogeneous wet snow samples. Therefore, we can only achieve a valid result in natural snowpacks when applying to an homogeneous layer of wet snow. Nevertheless, the results may be incorporated into snow-cover energy-balance models to improve the retention and percolation predictions. The thickness of the water-saturated layer observed at the base of the sample in our experiments, was related to the ratio of the mean convex radius of curvature to dry density.

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Experimental studies on the transformation from firn to ice in the wet-snow zone of temperate glaciers

Annals of Glaciology ◽

10.1017/s0260305500012143 ◽

1997 ◽

Vol 24 ◽

pp. 181-185 ◽

Cited By ~ 3

Author(s):

Katsuhisa Kawashima ◽

Tomomi Yamada

Keyword(s):

Experimental Studies ◽

Ice Formation ◽

Compression Tests ◽

Densification Rate ◽

Overburden Pressure ◽

Proportionality Constant ◽

Wet Snow ◽

Water Saturated ◽

The Relationship ◽

Good Agreement

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.

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Hydraulic and Diffusive Properties of Clay-Based Backfill Material for a Low-and Intermediate-Level Waste Repository

MRS Proceedings ◽

10.1557/proc-353-299 ◽

1994 ◽

Vol 353 ◽

Author(s):

W.J. Cho ◽

J.O. Lee ◽

P.S. Hahn ◽

H.H. Park

Keyword(s):

Diffusion Coefficients ◽

Experimental Studies ◽

Clay Content ◽

Dry Density ◽

Compacted Clay ◽

Southeastern Part ◽

Apparent Diffusion Coefficients ◽

Crushed Granite ◽

Apparent Diffusion ◽

Water Saturated

AbstractThe results of experimental studies performed to determine the radionuclide diffusion coefficients in a compacted clay and the hydraulic conductivities of clay/crushed granite mixtures with various clay contents are presented. Clay used in the experiments is a natural clay from the southeastern part of Korea, and it contains mainly calcium bentonite. The hydraulic conductivities of clay/crushed granite mixtures decreased with increasing clay content. In case of clay content of 50 wt.%, they maintain the considerably lower values even at the dry density of 1.5 Mg/m3. The diffusion coefficients for 90Sr, 137Cs, 60Co and 125I in water saturated clay at a dry density of 1.4 Mg/m3 were measured at room temperature. The average apparent diffusion coefficients obtained are 4.5 × 10−12 m2/s, 9.0 ×10−13 m2/s, 3.4 × 10−13 m2/s and 6.7 × 10−11 m2/s for 90Sr, 137Cs, 60Co, and 125I, respectively.

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Experimental studies on the transformation from firn to ice in the wet-snow zone of temperate glaciers

Annals of Glaciology ◽

10.3189/s0260305500012143 ◽

1997 ◽

Vol 24 ◽

pp. 181-185 ◽

Cited By ~ 3

Author(s):

Katsuhisa Kawashima ◽

Tomomi Yamada

Keyword(s):

Experimental Studies ◽

Ice Formation ◽

Compression Tests ◽

Densification Rate ◽

Overburden Pressure ◽

Proportionality Constant ◽

Wet Snow ◽

Water Saturated ◽

The Relationship ◽

Good Agreement

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.

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Acoustic Emission Characteristics of Compressive Deformation and Failure of Siltstone under Different Water Contents

Advances in Materials Science and Engineering ◽

10.1155/2017/4035487 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13 ◽

Cited By ~ 3

Author(s):

Lei Chen ◽

Jian Zhao ◽

Zhiyang Zheng

Keyword(s):

Acoustic Emission ◽

Water Content ◽

Count Rate ◽

Water Saturation ◽

Peak Stress ◽

Liaoning Province ◽

Open Pit ◽

Deformation And Failure ◽

Deformation Phase ◽

Water Saturated

The uniaxial compression and acoustic emission (AE) monitoring of siltstone specimens in the Gongchangling open-pit iron mine in Liaoning Province was conducted by evaluating the effects of three water saturation levels: dry, natural, and water-saturated. The siltstone AE characteristics were analyzed according to water content; the relationship between the AE characteristics and the growth and expansion of siltstone cracks was subsequently discussed. Research results indicated the following: siltstone specimens had distinctly different mechanical properties and AE characteristics according to water content; as the water content increased the compressive strength and elasticity modulus of specimens decreased. In the compacting phase of specimens under compression, the AE count rate of the water-saturated specimen was relatively small and the events were relatively stable. In the linear-elastic deformation phase, the AE count rate of the dry specimen increased sharply, reaching approximately 400 times/s. In the plastic yield deformation phase, the peak value of the AE count rate of the dry specimen ranged between 955 and 1,068 times/s, whereas that of the water-saturated specimen only attained a range of 635 to 782 times/s. In the failure phase, the time to reach the peak stress value of the dry specimen was increased as compared to that of the AE count rate.

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Investigation on Wet-Snow Metamorphism in Respect of Liquid-Water Content

Annals of Glaciology ◽

10.3189/s0260305500007576 ◽

1989 ◽

Vol 13 ◽

pp. 22-26 ◽

Cited By ~ 37

Author(s):

E. Brun

Keyword(s):

Growth Rate ◽

Water Content ◽

Liquid Water ◽

Liquid Water Content ◽

Snow Metamorphism ◽

Wet Snow ◽

The Mean ◽

Water Saturated ◽

Warming Device ◽

Snow Samples

Up to the present time, quantitative investigations on wet-snow metamorphism have mostly been conducted on water-saturated snow, because of the difficulty in getting large enough wet-snow samples at a uniformly low liquid-water content. Using the dielectric properties of snow at a frequency in the range 20–100 kHz, a warming device has been developed which has enabled us to bring samples of 7 × 10−3 m3 snow to any desired liquid-water content. A maximum value of 8% by volume was reached within 2 h.The warming device was used to reproduce natural wetness conditions in the laboratory in order to investigate wet snow metamorphism at low liquid-water content. Snow samples were brought to different liquid-water contents and held in that condition for about 2 weeks, during which grain-size was characterized using a picture-analysis system able to derive the mean radius of curvature of the cluster circumference. At any given liquid-water content value, the growth rate of the mean volume of the crystals building the clusters was constant, a pattern which has also been observed in water-saturated snow by previous investigators. This growth rate is well described by a power function of liquid-water content.

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Investigation on Compressibility and Microstructure Evolution of Intact Loess During Wetting Process

10.21203/rs.3.rs-1026244/v1 ◽

2021 ◽

Author(s):

Tao Jian ◽

Ling-wei Kong ◽

Wei Bai ◽

Zhi-liang Sun

Keyword(s):

Water Content ◽

Pore Space ◽

Experimental Studies ◽

Vertical Stress ◽

Dry Density ◽

Compression Index ◽

Rapid Reduction ◽

Before And After ◽

Wetting Process ◽

Intact Loess

Abstract Loess is widely deposited in arid and semi-arid areas and is characterized by low dry density, developed pore space, and loose structure, which is not commensurate with that high structural strength and shear strength in the dry state. Many natural phenomena and experimental studies show that intact loess is very sensitive to the change of water content, with slight increases in water content causing a rapid reduction in strength. Abundant information is available in the literature for collapsibility of loess; however, the research on the evolution of loess compressibility during wetting is still minimal, which is very helpful to understand the loess collapsible deformation caused by long-term irrigation. In this paper, the evolution of compressibility of intact loess during wetting are studied by oedometer test, and the microstructure and pore size distribution (PSD) is characterized on intact loess specimens with different water content before and after oedometer tests by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) methods. The results show that the compression index (Cc) and secondary compression index (Cα) of intact loess depend on water content and vertical stress and change abruptly after the vertical stress exceeds the yield stress. The Cα/Cc values of the intact loess are not constant, which increased with the vertical stress to peak and then gradually decreased and tend to 0.025. Both wetting and loading can cause microstructural damage to the intact loess, in which loading leads to the collapse of the overhead structure and transformation from a bimodal PSD into a single PSD, and wetting intensifies the collapse of microstructure to form a compacted interlocking structure and promotes the transformation of medium pores into small pores.

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The Storage of Water in, and Hydraulic Characteristics of, the Firn of South Cascade Glacier, Washington State, U.S.A.

Annals of Glaciology ◽

10.3189/s0260305500007667 ◽

1989 ◽

Vol 13 ◽

pp. 69-75 ◽

Cited By ~ 7

Author(s):

Andrew G. Fountain

Keyword(s):

Water Saturation ◽

Washington State ◽

Diurnal Fluctuation ◽

Water Volume ◽

Average Thickness ◽

Hydraulic Characteristics ◽

A Value ◽

Saturated Layer ◽

Melt Water ◽

Water Saturated

The porosity and water saturation of the firn of South Cascade Glacier were measured in order to determine both the volume of water stored in it and the significance of this water content for the water volume stored in the glacier. The distance to water below the firn surface was found never to be greater than 4 m, and the average thickness of the water-saturated layer was estimated to be 1.25 m. The average firn porosity was 0.15, the water saturation was 0.61, and the total volume of water stored in the firn was approximately 1.78 × 105m3representing about 12% of the total spring storage. The water table was found to exhibit a pattern of diurnal fluctuation which starts in late June or early July, indicating that melt water from the accumulation zone may pressurize the bed at diurnal frequencies. The depth-averaged permeability was found to be 1.5 × 10−5m/s, a value which compares favorably with those from other studies.

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Investigation on Wet-Snow Metamorphism in Respect of Liquid-Water Content

Annals of Glaciology ◽

10.1017/s0260305500007576 ◽

1989 ◽

Vol 13 ◽

pp. 22-26 ◽

Cited By ~ 55

Author(s):

E. Brun

Keyword(s):

Growth Rate ◽

Water Content ◽

Liquid Water ◽

Liquid Water Content ◽

Snow Metamorphism ◽

Wet Snow ◽

The Mean ◽

Water Saturated ◽

Warming Device ◽

Snow Samples

Up to the present time, quantitative investigations on wet-snow metamorphism have mostly been conducted on water-saturated snow, because of the difficulty in getting large enough wet-snow samples at a uniformly low liquid-water content. Using the dielectric properties of snow at a frequency in the range 20–100 kHz, a warming device has been developed which has enabled us to bring samples of 7 × 10−3 m3 snow to any desired liquid-water content. A maximum value of 8% by volume was reached within 2 h. The warming device was used to reproduce natural wetness conditions in the laboratory in order to investigate wet snow metamorphism at low liquid-water content. Snow samples were brought to different liquid-water contents and held in that condition for about 2 weeks, during which grain-size was characterized using a picture-analysis system able to derive the mean radius of curvature of the cluster circumference. At any given liquid-water content value, the growth rate of the mean volume of the crystals building the clusters was constant, a pattern which has also been observed in water-saturated snow by previous investigators. This growth rate is well described by a power function of liquid-water content.

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