Acid rain intrusion effects on the compressibility behaviour of residual soils

BakhshipourZeinab,; Asadi, Afshin; SridharanAsuri,; HuatBujang, B K

doi:10.1680/jenge.15.00081

Cited by 20 publications

(6 citation statements)

References 39 publications

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“…Ambas imagens apresentam uma estrutura cristalina em camadas ou pacotes. Segundo Bakhshipour et al (2017), as estruturas cristalinas dos solos dispostas em camadas, constituídos principalmente por caulinita, ao interagirem com ácido sulfúrico, sofrem modificações e suas microestruturas tornam-se semelhantes a agulhas ou em formas de fibras. Tal evidência não foi verificada nas amostras de caulim, em ambos ensaios, as quais mantiveram o formato característico do mineral de origem após exposição ao ácido, como pode ser observado na Figura 2 (b).…”

Section: Amostraunclassified

Avaliação das modificações microestruturais de geomaterial submetido a contaminação ácida sob diferentes metodologias

Levandoski¹,

Tímbola²,

Ferrazzo³

et al. 2020

Congresso Brasileiro De Mecânica Dos Solos E Engenharia Geotécnica

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A exposição de geomateriais à lixiviados ácidos pode provocar alterações em sua microestrutura em função da dissolução de metais, dessorção de espécies químicas e dissolução parcial de minerais. Modificações nas propriedades dos geomateriais expostos a condições de extrema acidez ainda necessitam de maiores investigações. Sendo assim, este trabalho avaliou a microestrutura de amostras de caulim submetidas à contaminação por ácido sulfúrico nas concentrações de 0,00 e 1,00 mol/L, em ensaios de batelada e de consolidação. As amostras ensaiadas foram caracterizadas por espectrometria de fluorescência de raios X, difração de raios X e microscopia eletrônica de varredura. O contato com a solução ácida de 1,00 mol/L resultou na solubilização de alguns minerais constituintes do caulim, com perda de albita, bem como a formação de mineral sulfatado, corroborando o aumento do teor de óxido de enxofre. A morfologia das partículas do caulim não sofreu alterações decorrentes da exposição ao ácido sulfúrico.

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Section: Amostraunclassified

Avaliação das modificações microestruturais de geomaterial submetido a contaminação ácida sob diferentes metodologias

Levandoski¹,

Tímbola²,

Ferrazzo³

et al. 2020

Congresso Brasileiro De Mecânica Dos Solos E Engenharia Geotécnica

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“…However, the amount of dry-wet cycles was positively correlated with the expansion rate at the early times, then stabilizes at the late times, with a large increas after two epochs of action. Bakhshipour et al [12] studied the influence of acid rain intrusion on the compression performance of residual soil; Liu et al [13][14][15] found the uniaxial compressive strength, elastic modulus, cohesion, internal friction angle, and triaxial compressive strength decreased with the increase of dry-wet cycles. Liu and Gui [16] concluded that the shear strength and cohesion of montmorillonite-quartz sand remolded soil decreased due to the reaction of H + ion and montmorillonite under acidic conditions.…”

Section: Introductionmentioning

confidence: 99%

Influence of acid rain and root reinforcement coupling factors on disintegration characteristics of expansive soil

et al. 2023

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The effect of soil fixation and anti-scour instability of slope vegetation generally depends on the strength and anti-disintegration ability of slope soil due to increase of root system. Therefore, it is particularly necessary to study the disintegration characteristics of expansive soil related to slope instability under acidic conditions (simulated acid rain). In this paper, the response surface method (RSM) was used with the pH value, root diameter, root length, root coefficient, and distribution as independent variables, and the disintegration amount of root-soil (DARS) after 60min as the response value. Then X-ray diffractometer (XRD) was used to analyze the mineral composition changes of the sample under this environment. Simultaneously, the plasticity index of expansive soil at different values of pH was studied to discuss the disintegration mechanism of root compound expansive soil in an acid environments. The results show that the root system improves the anti-disintegration characteristics of the root-soil, and the effects of various factors on the amount of disintegration were as follows: root length > pH value > root distribution > root amount > root diameter. The DARS with a length of 20mm increased by 26.67% and 41.56% compared to the 30mm and 40mm. Compared to the horizontal distribution and horizontal + slant distribution, the DARS with slant distribution was increases by 11.39% and 20.24% respectively. The DARS with 2 roots is increased by 9.92% and 16.75% compared to 4 and 6 roots respectively. The 1mm diameter DARS is 6.65% and 15.49% higher than the 2mm and 3mm, respectively. In addition, an acidic environments can lead to an increase in the amount of disintegration or rate of disintegration. The disintegration at pH = 4.2 was increased by 11.4% and 22.4% compared to pH = 5.6 and pH = 7, respectively. The acidity affects soil disintegration is due to the hydrophilic minerals in the expansive soil react with H+ ion in the acid solution to form soluble salts. Due to the dissociation and leaching of free quartz and metal oxides in the soil to varying degrees, the ability of expansive soil to accumulate is reduced. The intensity of erosion and leaching decreases with increasing pH. In addition, the pH value can affects the plasticity index of the soil, which increases with the increasing pH, thus affects the disintegration properties of the expansive soil.

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“…Besides, acid rain would accelerate the precipitation of calcium ions in light soil and increase soil permeability [12]. As a result, the acid rain would destroy the soil structure, causing the loss of metal ions such as iron and aluminum from the soil matrix [13,14]. e lower the pH value of infiltration acid rain, the greater the compressibility of the soil.…”

Section: Introductionmentioning

confidence: 99%

Study on Hygroscopic Swelling and Dehumidification Cracking Characteristics of Expansive Soil under Acid Rain and Cyclic Drying‐Wetting

Chang

Xiao

Jiang

et al. 2021

Advances in Civil Engineering

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In this study, to reveal the swelling and cracking characteristics of expansive soil subjected to cyclic drying-wetting of acid rain, the effects of acid rain and cyclic drying-wetting on the swelling deformation of expansive soil were studied by using the load-free swelling rate test. Afterward, a high-definition digital camera was used to capture the crack development images of the sample during the dehumidification process under cyclic drying-wetting of acid rain. Furthermore, the changes of the microstructure and mineral composition of the expansive soil after cyclic drying-wetting of acid rain were analyzed by using the scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests. Finally, the effect mechanisms of acid rain and cyclic drying-wetting on the swelling deformation and crack development of the expansive soil were discussed. The results indicate that acid rain has a positive effect on the swelling deformation and crack development of the expansive soil. The effect is greater with a stronger acidity of rainfall. Moreover, the combined action of acid rain and cyclic drying-wetting can promote the swelling deformation and crack development of the sample more notably. The swelling rate of the sample increased most significantly during the first two-time cyclic drying-wetting. The measured swelling rates at pH = 3 and 5 are 23.7% and 20.6%, respectively, which are higher than the swelling rates of 19.0% at pH = 7. The humidity of samples is 17–18% after the first-time drying-wetting cycle. The crack area ratios (Mf) of the samples with pH values of 5 and 3 are, respectively, increased by 11.0% and 69.1%; the average crack width of the sample increases by 32.3% and 93.3%, respectively, compared with pH values of 7. After the fourth-time drying-wetting cycle, Mf and the average crack width of the samples under the rainwater environment of three pH values increase greatly, but the difference of Mf among them became unapparent. In addition, the microscopic test results show that acid rain can corrode the binding materials (e.g., SiO2, Al2O3, K2O, MgO, and CaO) in the expansive soil. The erosion of the binding minerals weakens the structural connection strength, resulting in continuous increases in both size and number of microvoids. Under the superimposed influence of cyclic drying-wetting, the above changes are even more dramatic. Macroscopically, the swelling deformation of expansive soil increases and the cracks develop rapidly.

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Acid rain intrusion effects on the compressibility behaviour of residual soils

Cited by 20 publications

References 39 publications

Avaliação das modificações microestruturais de geomaterial submetido a contaminação ácida sob diferentes metodologias

Avaliação das modificações microestruturais de geomaterial submetido a contaminação ácida sob diferentes metodologias

Influence of acid rain and root reinforcement coupling factors on disintegration characteristics of expansive soil

Study on Hygroscopic Swelling and Dehumidification Cracking Characteristics of Expansive Soil under Acid Rain and Cyclic Drying‐Wetting

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