Impact of Cooling on Water and Salt Migration of High-Chlorine Saline Soils

Geofluids ◽

10.1155/2021/8612762 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Runze Tian ◽

Yu Zhang ◽

Anhua Xu ◽

Xuemei Li ◽

Yunlong Hou ◽

...

Keyword(s):

Phase Transition ◽

Water Content ◽

Saline Soil ◽

Water Phase ◽

Saline Soils ◽

Initial Water Content ◽

Cooling Process ◽

Crystallization Water ◽

Initial Water ◽

Salt Migration

Secondary salinization is a common problem in saline soil projects. In order to grasp the mechanism of water and salt migration of high-chlorine saline soil during the cooling process, the saline soils along the Qarhan-Golmud Highway in the Qinghai-Tibet Plateau were selected as test samples. Firstly, the basic physical parameter test and the soluble salt chemical experiment were carried out and obtained liquid and plastic limits, dry density, etc. Secondly, freezing temperature experiments and water-salt migration experiments under one-way cooling conditions were conducted according to the actual environmental conditions, and after the temperature gradient line of the soil sample was stable, water content and labile salt chemistry experiments were conducted to obtain the distribution of water and salt contents of soil samples. Finally, the effect of crystallization-water phase transition on water and salt migration and the effect of chloride salt on the temperature of crystallization-water phase transition were considered, and a mathematical model applicable to the water and salt migration of highly chlorinated saline soils under the effect of unidirectional cooling was established and solved with COMSOL Multiphysics software, and the correctness of the model was verified by comparing the simulation results with the experimental results. The study found that (1) during the one-way cooling process, both water and salt showed a tendency to migrate to the cold end. The MC (saline soil with medium chlorine content) with an initial water content of 16.9% and Cl− content of 3.373% was measured to reach a 17.6% water content and 3.76% Cl− content at the cold (top) end after the experiment. The HC (saline soil with high chlorine content) with an initial water content of 6.6% and Cl− content of 17.928% was measured to reach a 6.83% water content and 18.8% Cl− content after the experiment and (2) after the one-way cooling experiment of the MC, the water content at a distance of 1–2 cm from the cold end has abrupt changes, which may be caused by a small amount of crystallization—water phase transition at this location. At the same time, according to the temperature change graph during the cooling process, the phase change temperature was set to −9°C in the numerical simulation process to match the experimental results.

Using ANFIS and BPNN Methods to Predict the Unfrozen Water Content of Saline Soil in Western Jilin, China

Symmetry ◽

10.3390/sym11010016 ◽

2018 ◽

Vol 11 (1) ◽

pp. 16 ◽

Cited By ~ 1

Author(s):

Yufeng Liu ◽

Qing Wang ◽

Xudong Zhang ◽

Shengyuan Song ◽

Cencen Niu ◽

...

Keyword(s):

Water Content ◽

Saline Soil ◽

Salt Content ◽

Frozen Soil ◽

Unfrozen Water ◽

Initial Water Content ◽

Initial Water ◽

Inference System ◽

Unfrozen Water Content ◽

Western Jilin

: Saline soil in seasonally frozen soil areas has caused tremendous damage to engineering and the ecological environment. The unfrozen water is the main factor affecting the properties of saline soil in seasonally frozen soil area and therefore needs to be studied. However, due to the high cost of laboratory measurement of the unfrozen water content, this study focuses on using an adaptive network fuzzy inference system (ANFIS) and a back propagation neural network (BPNN) to predict the unfrozen water content of saline soil in the Zhenlai area, Western Jilin. The data for the constructed model is obtained by nuclear magnetic resonance (NMR) testing. The initial water content (W0), salt content (S), and temperature (T) are used as input parameters for predicting the unfrozen water content (Wu). The results of the ANFIS and BPNN models are compared. The results show that although both methods are suitable for predicting the unfrozen water content of saline soil in the Zhenlai area, western Jilin, the prediction accuracy of the ANFIS model is higher.

Investigation into Freezing Point Depression in Soil Caused by NaCl Solution

Water ◽

10.3390/w12082232 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2232 ◽

Cited By ~ 1

Author(s):

Feng Ming ◽

Lei Chen ◽

Dongqing Li ◽

Chengcheng Du

Keyword(s):

Water Content ◽

Water Activity ◽

Salt Concentration ◽

Freezing Point ◽

Saline Soil ◽

Initial Water Content ◽

Freezing Point Depression ◽

Initial Water ◽

Important Indicator ◽

Critical Water Content

Engineering practices illustrate that the water phase change in soil causes severe damage to roads, canals, airport runways and other buildings. The freezing point is an important indicator to judge whether the soil is frozen or not. Up to now, the influence of salt on the freezing point is still not well described. To resolve this problem, a series of freezing point tests for saline soil were conducted in the laboratory. Based on the relationship between the freezing point and the water activity, a thermodynamic model considering the excess Gibbs energy was proposed for predicting the freezing point of saline soil by inducing the UNIQUAC (universal quasi-chemical) model. The experimental results show that the initial water content has little influence on the freezing point if the initial water content is higher than the critical water content, while the freezing point decreases with the decrease of the water content if the initial water content is lower than the critical water content. Moreover, it is found that the freezing point is related to the energy status of liquid water in saline soils and it decreases with the increase of the salt concentration. Moreover, the freezing point depression of saline soil is mainly caused by the decrease of water activity. Compared with the other two terms, the residual term, accounting for the molecular interactions, has an obvious influence on the water activity. This result is helpful for understanding how salt concentration affects the freezing point of saline soil and provides a reference for engineering construction in saline soil areas.

Influence of initial water content and strain rate on remolded yield stress in marine clay

Marine Georesources and Geotechnology ◽

10.1080/1064119x.2021.1892246 ◽

2021 ◽

pp. 1-8

Author(s):

Xiaobing Li ◽

Jianpeng Chen ◽

Xiuqing Hu ◽

Hongtao Fu ◽

Jun Wang ◽

...

Keyword(s):

Strain Rate ◽

Water Content ◽

Yield Stress ◽

Initial Water Content ◽

Marine Clay ◽

Initial Water

Application of the Calorimetric Methods to the Characteristics of Seeds from Olives

Proceedings ◽

10.3390/foods_2020-07665 ◽

2020 ◽

Vol 70 (1) ◽

pp. 90

Author(s):

Andrzej Bryś ◽

Joanna Bryś ◽

Marko Obranović ◽

Dubravka Škevin ◽

Szymon Głowacki ◽

...

Keyword(s):

Olive Oil ◽

Water Content ◽

Cooling System ◽

Waste Product ◽

Normal Pressure ◽

Ash Content ◽

Initial Water Content ◽

Scanning Calorimetry ◽

Initial Water

The olive oil industry represents an important productive sector in the Mediterranean basin countries. Olive stone is an essential by-product generated in the olive oil extraction industries and it represents roughly 10% by weight of the olive fruit. The seeds of pickled olives are also a significant waste product. In the present study, we have investigated the possibility of the use of differential scanning calorimetry for the thermal characterization of seeds from green and black pickled olives from Croatia. The differential scanning calorimeter (DSC) with a normal pressure cell equipped with a cooling system was used to determine the thermal properties of seeds from olives. The following analyses were also performed: the determination of calorific values in a pressure bomb calorimeter, the determination of initial water content, the determination of changes of water content during drying at the temperatures of 30 °C, 50 °C and 80 °C, the determination of a percentage content of seeds mass to the mass of the whole olives, and the determination of ash content. Seeds from olives are characterized by very good parameters as a biomass. The analyzed olive seeds were characterized by low water content, low ash content, and a relatively high caloric value.

Initial Water Content and Temperature Effects on Electrokinetic Removal of Aluminium in Drinking Water Sludge

Physics Procedia ◽

10.1016/j.phpro.2009.11.058 ◽

2009 ◽

Vol 2 (3) ◽

pp. 1021-1030 ◽

Cited By ~ 6

Author(s):

M. Cherifi ◽

S. Hazourli ◽

M. Ziati

Keyword(s):

Drinking Water ◽

Water Content ◽

Temperature Effects ◽

Initial Water Content ◽

Initial Water

Effects of Initial Water Content on Microstructure and Mechanical Properties of Lean Clay Soil Stabilized by Compound Calcium-Based Stabilizer

Materials ◽

10.3390/ma11101933 ◽

2018 ◽

Vol 11 (10) ◽

pp. 1933 ◽

Cited By ~ 6

Author(s):

Chenglong Yin ◽

Wei Zhang ◽

Xunli Jiang ◽

Zhiyi Huang

Keyword(s):

Water Content ◽

Soil Stabilization ◽

Clay Soil ◽

Soil Aggregates ◽

Optical Microscope ◽

Initial Water Content ◽

Reaction Products ◽

Unconfined Compression Test ◽

Initial Water ◽

X Ray

Initial water content significantly affects the efficiency of soil stabilization. In this study, the effects of initial water content on the compressibility, strength, microstructure, and composition of a lean clay soil stabilized by compound calcium-based stabilizer were investigated by static compaction test, unconfined compression test, optical microscope observations, environment scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The results indicate that as the initial water content increases in the range studied, both the compaction energy and the maximum compaction force decrease linearly and there are less soil aggregates or agglomerations, and a smaller proportion of large pores in the compacted mixture structure. In addition, for specimens cured with or without external water supply and under different compaction degrees, the variation law of the unconfined compressive strength with initial water content is different and the highest strength value is obtained at various initial water contents. With the increase of initial water content, the percentage of the oxygen element tends to increase in the reaction products of the calcium-based stabilizer, whereas the primary mineral composition of the soil-stabilizer mixture did not change notably.

Solidification of High Organic Matter Content Sludge by Cement, Lime and Metakaolin

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.12293 ◽

2018 ◽

Author(s):

Ke Rui ◽

Wang Hongxing ◽

Tan Yunzhi ◽

Wang Lehua

Keyword(s):

Organic Matter ◽

Water Content ◽

Organic Matter Content ◽

Microscopic Analysis ◽

Chemical Components ◽

Orthogonal Experimental Design ◽

Initial Water Content ◽

Initial Water ◽

Lime Content ◽

Sheet Structure

Based on orthogonal experimental design, the key solidification controlling technology of Solidified/Stabilized (S/S) sludge with high total organic content (TOC) by cement, lime and metakaolin was explored by macroscopic tests, chemical components measurements and microscopic analysis. The macroscopic tests show that, the permeability coefficient is mainly affected by initial water content and lime content, and the unconfined compression strength is mainly affected by cement content and lime content. The chemical components measurements show that, the solidification effect of S/S sludge with high TOC is controlled by organic matter consumption, and organic matter consumption is determined by the alkaline environment from the cement and lime hydration reactions, which is mainly affect by the initial water content and lime-metakaolin content ratio. The microscopic analysis results show that, lime consumes parts of organic matter while excess lime produces weak Ca(OH)2 crystal fluffy sheet structure, matakaolin produces pozzolanic reactions with cement and lime instead of soil particles, and consumes the weak Ca(OH)2 crystal fluffy sheet structure produced by superfluous lime. The research has confirmed key controlling points of S/S sludge in case of high TOC, which will provide theoretical guidance and technical support for S/S sludge promotion with high TOC.

Determination of the tensile strength of unsaturated tailings using bending tests

Canadian Geotechnical Journal ◽

10.1139/cgj-2014-0156 ◽

2015 ◽

Vol 52 (11) ◽

pp. 1874-1885 ◽

Cited By ~ 9

Author(s):

Bibiana Narvaez ◽

Michel Aubertin ◽

Faustin Saleh-Mbemba

Keyword(s):

Tensile Strength ◽

Water Content ◽

Water Retention ◽

Water Retention Curve ◽

Initial Water Content ◽

Ambient Conditions ◽

Initial Water ◽

Bending Tests ◽

Retention Curve ◽

Apparent Cohesion

Bending tests were conducted on specimens of unsaturated tailings from three hard rock mines to evaluate their tensile strength. Saturated samples were prepared at an initial water content, w0, of 40% and then naturally dried under ambient conditions to pre-selected degrees of saturation, Sr, which can be related to the corresponding suction using the water retention curve. The basic interpretation of the bending tests results is based on an elastic–brittle behavior. The results show how the tensile strength, σt, of unsaturated tailings varies with water content, w (and Sr). The experimental data are also used to evaluate Young’s modulus in tension, Et, and to estimate the apparent cohesion, capp, as a function of Sr. Predictive equations are also applied to estimate the values of σt of unsaturated tailings using the water retention curve.

Temperature and seed moisture content affect electrical conductivity test in pea seeds

Journal of Seed Science ◽

10.1590/2317-1545v39n4181021 ◽

2017 ◽

Vol 39 (4) ◽

pp. 410-416 ◽

Cited By ~ 1

Author(s):

Lara Bernardes da Silva Ferreira ◽

Nayara Alves Fernandes ◽

Luan Costa de Aquino ◽

Anderson Rodrigo da Silva ◽

Warley Marcos Nascimento ◽

...

Keyword(s):

Electrical Conductivity ◽

Moisture Content ◽

Water Content ◽

Initial Water Content ◽

Seed Moisture Content ◽

Initial Water ◽

Test Efficiency ◽

Seed Moisture ◽

Pea Seeds ◽

Initial Seed

Abstract: Several factors affect the electrical conductivity test efficiency, with emphasis given to the initial water content and the temperature during imbibition. This study aimed to evaluate the effect of the initial water content of pea seeds and the temperature on the electrical conductivity test efficiency. Six lots of ‘Mikado’ pea were used, which were previously tested for initial characterization. In the first trial, based on the initial value of the samples, the seed moisture content was adjusted to 9, 11, 13 and 15% and then the seeds were submitted to the electrical conductivity test. In the second trial, the water for seed imbibition was kept for 24 hours at 10, 15, 20, 25 and 30 ºC, and after that time the seeds were added and soaked for other 24 hours at the temperatures already mentioned. It was observed that initial seed moisture content and water temperature during imbibition influenced the results of the electrical conductivity test. This test should be carried out with distilled water, previously maintained for 24 hours at 25 °C for temperature stabilization. Then, the seeds with seed moisture content between 11 and 15% should be put to soak at 25 °C, and maintained at this temperature for 24 hours.

Study on the Mechanical Criterion of Ice Lens Formation Based on Pore Size Distribution

Applied Sciences ◽

10.3390/app10248981 ◽

2020 ◽

Vol 10 (24) ◽

pp. 8981

Author(s):

Yuhang Liu ◽

Dongqing Li ◽

Lei Chen ◽

Feng Ming

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Water Content ◽

Size Distribution ◽

Initial Water Content ◽

Mean Stress ◽

Initial Water ◽

Unfrozen Water Content ◽

The Mean ◽

Lens Formation

Ice lens is the key factor which determines the frost heave in engineering construction in cold regions. At present, several theories have been proposed to describe the formation of ice lens. However, most of these theories analyzed the ice lens formation from a macroscopic view and ignored the influence of microscopic pore sizes and structures. Meanwhile, these theories lacked the support of measured data. To solve this problem, the microscopic crystallization stress was converted into the macro mean stress through the principle of statistics with the consideration of pore size distribution. The mean stress was treated as the driving force of the formation of ice lens and induced into the criterion of ice lens formation. The influence of pore structure and unfrozen water content on the mean stress was analyzed. The results indicate that the microcosmic crystallization pressure can be converted into the macro mean stress through the principle of statistics. Larger mean stress means the ice lens will be formed easier in the soil. The mean stress is positively correlated with initial water content. At the same temperature, an increase to both the initial water content and the number of pores can result in a larger mean stress. Under the same initial water content, mean stress increases with decreasing temperature. The result provides a theoretical basis for studying ice lens formation from the crystallization theory.