Influence of Leachate on Properties and Regions of Compacted Clay Layer: A Column Experiment

Guo, Yuliang; Cao, Liwen; Feng, Xuehan; Liu, He

doi:10.1080/15320383.2019.1650002

Cited by 6 publications

(3 citation statements)

References 24 publications

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“…The structural deformation and strength change of soil under environmental change or external loading are the exterior manifestations of internal microstructural change [8][9][10][11]. In addition, increasing attention has been given to the characteristics and structure of clay contaminated by municipal waste [12][13][14]. The microstructure and pixel threshold value of municipal waste-contaminated clay notably affect the assessment of its engineering characteristics.…”

Section: Introductionmentioning

confidence: 99%

Determining Effective Threshold Range of Image Pixel Values for Municipal Waste-Contaminated Clay

Zhang,

Cao,

Guo

2024

Applied Sciences

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Currently, more attention has been given to the study of the microstructure of contaminated clay, while few studies have focused on the analysis of SEM images of clay from a threshold perspective. The purpose of this paper was to determine the threshold range of image pixel values for municipal waste-contaminated clay by observing and processing SEM images of municipal waste-contaminated clay under different seepage depths and concentrations. In this study, municipal waste-contaminated clay samples were obtained at different depths in a column test exhibiting different CaCO3 and CH3COOH concentrations, imaged through SEM and subjected to binarization. Three steps for determining the pixel threshold value of the SEM images were described, including preprocessing and binarizing the SEM images in Image Pro Plus 6.0 (IPP) and morphological processing by the Pores (Particles) and Cracks Analysis System V2.3 (PCAS). The apparent void ratio of contaminated clay and the fractal dimension of clay particles were applied as evaluation parameters. The determined effective threshold range of the image pixel values of municipal waste-contaminated clay was 110–140. The accuracy of this method was verified in three aspects: the relationship between the threshold value and the apparent void ratio, the variation in pore blockage with seepage depth, and the characteristics of the compaction factor with seepage depth and pollutant concentration.

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Section: Introductionmentioning

confidence: 99%

Determining Effective Threshold Range of Image Pixel Values for Municipal Waste-Contaminated Clay

Zhang,

Cao,

Guo

2024

Applied Sciences

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“…Thus, for example, in a study of waste leachate-induced structural changes in clay, Oztoprak et al [21] found that leachate effectively separated illite from clay by cation exchange, leading to structural disintegration, the formation of flocculated particle arrangements, and a reduction in clay strength. Additionally, through column tests, Guo et al [22] found that when leachate flow rate was low, the leachate and clay mainly underwent a chemical reaction whereby some alkaline pollutants in the clay were dissolved, consequently reducing the extent of soil particle cementation, clay strength, and clay ability to resist deformation. In order to further understand the mechanism of clay structural changes under leachate action, many researchers have conducted microcharacterization and adsorption tests to study the micro-mechanisms at play.…”

Section: Introductionmentioning

confidence: 99%

Effects of Red Mud Leachate on the Microstructure of Fly Ash-Modified Red Clay Anti-Seepage Layer under Permeation

Zhang,

Wang,

et al. 2023

Sustainability

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In recent years, the ecological safety issues of red mud tailings ponds have been frequent, with problems such as the seepage damage of anti-seepage materials at the bottom of tailings ponds, failure of anti-seepage systems, and leakage of pollutants. In order to deeply analyze the influence of red mud (RM) leachate on the microstructure of the modified red clay (RC) anti-seepage layer, this article explores the influence characteristics of strong alkaline RM leachate on the microstructure of a modified RC anti-seepage layer under actual working conditions through a combination of permeability tests and microscopic characterization. The results showed that as the RM leachate permeation time increased, varying changes occurred in the permeability coefficient of the modified RC with different FA contents, among which the permeability coefficient of the modified RC with an 8% FA content showed a significant decreasing trend, reaching 5.98 × 10−11 m/s after stabilization. After permeation, numerous small pores were generated in the modified clay; furthermore, the small particles of the FA-modified clay were significantly reduced compared to pure clay. As the permeation time increased, the 8% FA-modified RC showed a phenomenon of first increasing and then decreasing in specific surface area, with a small change from 27.71 m2/g to 27.52 m2/g, indicating that this sample had high stability and the specific surface area was not significantly affected by permeation. This is mainly caused by the influence of gelling materials produced by the pozzolanic reaction and activation effect upon FA addition. The soil structure became more compact at the microscopic level with increasing FA content, resulting in particle aggregation, increased specific surface area, and narrowed small-pore size distribution. After 60 days of permeation, the single-shoulder peak of the 8% FA-modified RC was still the lowest at about 0.30 dV/dr. Compared to other samples, the pore size was smaller and less affected by the leachate. Overall, the microstructure of the 8% FA-modified RC was less affected by the leachate. This study provides an explanatory basis for the macroscopic mechanical phenomena by analyzing the influence of microstructure. It further provides a reference for studying the selection of anti-seepage materials.

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“…Thus, having information on clayey soil distribution provides a thorough understanding in opposition to contamination spreading [5]. The contaminated soil can cause miscellaneous engineering problems represented by differential settlement, damage to structures due to soil leachate, cracking and inclination in the ground surface [15]. In addition, the locations and volumes of contaminated soils are necessary for remediation process.…”

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confidence: 99%

Investigation of distinctive physico-chemical soil correlations for Kirkuk city using spatial analysis technique incorporated with statistical modeling

Raheem

Omar

2021

Geo-Engineering

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In the sense of challenging economic situation, it is difficult to perform laboratory tests in a whole intended area to define the soil characteristics for whatever task or situation within an entire city. Hence, this study has used the spatial analysis through applying the inverse distance weighted (IDW) technique to integrate with the available data for 56 different soil samples collected from various depths of Kirkuk city. The studied characteristics were mainly classified to physical soil properties included gravel, sand, silt, and clay contents with chemical soil properties included organic and gypsum contents, pH content, sulfur trioxide, and total dissolved solids (TDS) content. Moreover, statistical investigations such as physico-chemical correlation, linear single and linear multi regression models have been applied. The results of this study have focused on constructing thematic digital maps for visualizing different physical and chemical characteristics of Kirkuk soil. In statistical analysis, negative linear correlations are obtained from the relation between the values of the pH, gypsum, organic, and SO3 contents with the increase of the gravel content, whereas a positive linear correlation is attained for the values of TDS content with the increase of the gravel content. Furthermore, the proposed linear multi regression model predicts the pH values reasonably where most of the values were close to the equality line. The obtained digital maps accompanied with the statistical models will provide comprehensive spatial, agricultural, chemical and mechanical visualizations of the nature and morphology of the soils in Kirkuk city.

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Influence of Leachate on Properties and Regions of Compacted Clay Layer: A Column Experiment

Cited by 6 publications

References 24 publications

Determining Effective Threshold Range of Image Pixel Values for Municipal Waste-Contaminated Clay

Determining Effective Threshold Range of Image Pixel Values for Municipal Waste-Contaminated Clay

Effects of Red Mud Leachate on the Microstructure of Fly Ash-Modified Red Clay Anti-Seepage Layer under Permeation

Investigation of distinctive physico-chemical soil correlations for Kirkuk city using spatial analysis technique incorporated with statistical modeling

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