Impact of Desalination on Physical and Mechanical Properties of Lanzhou Loess

Hui, Bing; Zhang, Ying; Ma, Min

doi:10.1134/s1064229317130014

Cited by 5 publications

(6 citation statements)

References 15 publications

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“…According to the 30% moisture content, the water will be sprayed evenly on the soil and thoroughly mixed before being placed in a bag and sealed for several hours to ensure uniform moisture content. In accordance with the geotechnical test specification and previous studies [36][37][38], the prepared test soil was loaded into the ring knife. Since the roadbed should be more than 90% compacted, the dry density of its straight shear sample is 1.395 g/cm 3 .…”

Section: Methodsmentioning

confidence: 99%

Study of Ion Adsorption and Shear Strength of Red Clay under Leaching Action

Song

Geng

et al. 2023

Sustainability

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To study the soil-water effect of red clay, a leaching test is conducted by loading red clay into a soil column and collecting the leaching waste liquid periodically for analysis of the ion content and conductivity changes in the leaching waste liquid. After leaching and filtering, the soil is removed from the column and reconstituted as a straight-shear specimen for a straight-shear test. Ca2+, Mg2+, and SO42- ions increased and then stabilized in water samples as leaching time increased, while Na+, Cl-, and NO3- declined and then stabilized. Due to their presence in the leaching solution, Ca2+, Mg2+, and SO42-ions are initially adsorbed by the soil and then saturated by adsorption. In contrast, Na+, Cl-, and NO3−precipitate out of the soil due to the dissolution and ion exchange of the soil sample, thereby weakening their effects. Consequently, these ions appear to vary in various ways. The relationship between ion content in solution and conductivity has also been discovere, and the conductivity varies with the total ion charge in the solution. The angle of internal friction decreases as the leaching time increases, but the cohesion of the soil increases.

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Section: Methodsmentioning

confidence: 99%

Study of Ion Adsorption and Shear Strength of Red Clay under Leaching Action

Song

Geng

et al. 2023

Sustainability

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“…From the perspective of water-soil chemical interactions, loess is rich in soluble salts and clay minerals, which are crucial components of soil cementing substances. Their content directly influences the disintegration, solubility, swelling, adhesion, permeability, and stability of loess [80,81]. The primary water-soil chemical interactions during loess disintegration under acidic conditions are dissolution [18,27,28,35,82] and cation exchange and adsorption [83].…”

Section: Water-soil Chemical Interactionsmentioning

confidence: 99%

Unraveling the Mystery of Water-Induced Loess Disintegration: A Comprehensive Review of Experimental Research

Chen,

Li,

Wang

et al. 2024

Sustainability

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Loess disintegration is a significant physicochemical and mechanical dissolution process that occurs when loess comes into contact with water. This phenomenon contributes to geological disasters such as loess cave erosion, landslides, and debris flows. The disintegration of loess can be influenced by both internal and external factors. Research on internal factors of loess disintegration has been widely recorded, but the research progress on external environmental factors that affect loess disintegration is not well summarized. This review summarizes the impacts of external water environmental factors on loess disintegration and reveals that six external water environmental factors, namely the temperature of the aqueous solution, hydrodynamic conditions, solution pH, salt concentration and type in the solution, freeze–thaw cycles, and dry–wet cycles, can significantly impact loess disintegration. Furthermore, this review delves into three key research areas in loess disintegration under the influence of these water environmental factors: experimental research on loess disintegration, the disintegration parameters used in such research and their variations, and the water–soil chemical reactions and microstructural changes during loess disintegration. It concludes that current experimental research on loess disintegration suffers from inadequate studies, with existing research associated with poor comparability and weak representativeness, and a lack of comprehensive, systematic analysis of its regularities of influence and response mechanisms from both microscopic and macroscopic perspectives. This paper can provide valuable insights for the prevention of loess geological disasters and engineering safety construction.

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“…Since 1968, the phreatic level in the center of the platform has increased by 20 m, with an average annual increase of 0.27 m, causing the loess to be under soaking state for a long-term period [24,27]. Due to the unique geological environment, salt minerals of weathered rocks are abundant within the loess soils [23,25], and thus salt loss in the loess is common, triggering a large number of loess landslides in the Heifangtai area due to irrigation (Figure 1). The sampling site, which was selected at a distance of about 10 m away from the top of the platform, is located in the Dangchuan landslide in Heifangtai terrance in which salt deposits were commonly observed due to the long-term irrigation activities (Figure 1b).…”

Section: Test Samplesmentioning

confidence: 99%

“…It has been shown that the NaCl concentration can have a fundamental influence on the shear behavior of loess soils [19,22,25]. Fan et al, [17] has reported that the shear strength of saturated loess soils increases as the NaCl concentration increases, while some other researchers have concluded that the increase of NaCl concentration leads to the reduction in shear strength of saturated loess soils [22,45].…”

Section: The Peak Shear Strength and Residual Strengthmentioning

confidence: 99%

“…Furthermore, it was found that the peak strength and residual strength of saturated loess were strongly modified by the variation in NaCl (sodium chloride) concentration of groundwater [19], and Zhang et al [19] also pointed that the shear strength shows a non-linear trend of increasing with NaCl concentration, while the microstructural characterization of loess samples was not mentioned. Bing et al [25] studied the effect of desalination on the physical and mechanical properties of loess and found that the calcium cementation of loess after desalination was weakened and the structure was also changed. More recently, Fu et al [18] pointed out that as the salt content in loess increases from 0.00% to 12.00%, the cohesive angle and internal friction angle of loess both decrease first and then increase, while the mechanical mechanism of loess due to the variation in microstructure of loess was not investigated.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Soaking Time and Salt Concentration on Mechanical Characteristics of Slip Zone Soil of Loess Landslides

Xue¹,

Wang²,

Li³

2020

Water

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Loess landslides are closely related to the variation in mechanical properties of soils due to the leaching of irrigation water in the irrigation area which causes the loss of soluble salt in the loess stratum. To investigate the effect of leaching on the mechanical characteristics of loess, ring shear tests were conducted on the slip zone soil samples obtained from a typical loess landslide under different soaking time and salt concentration. Furthermore, the microstructural observations were made on shear planes by using SEM (scanning electron microscopy) tests. The experiment revealed that: firstly, the shear strength of loess decreases with the increase of soaking time before reaching the minimum value at the soaking time of 1 d, and then increases with the soaking time until reaching a relatively stable value. Secondly, the shear strength of loess has an increasing tendency with the salt concentration before reaching a maximum value at the salt concentration of 8%, and then shear strength decreases. In addition, a “stress-softening” was found for the loess samples with the soaking time of 1 d and salt concentration of 8%. It is found that the total number of micropores and small-pores in loess samples decreases with increasing salt concentration up to 8%, but increases rapidly between salt contents of 8% and 20%. The SEM tests showed that the increase in salt concentration (0% to 8%) facilities the formation of small aggregates within loess soils, which in turn promotes the increasing of shear strength. However, further increase in salt concentration (8% to 20%) helps the development of relatively large aggregates in loess samples, resulting in the reduction in shear strength.

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Impact of Desalination on Physical and Mechanical Properties of Lanzhou Loess

Cited by 5 publications

References 15 publications

Study of Ion Adsorption and Shear Strength of Red Clay under Leaching Action

Study of Ion Adsorption and Shear Strength of Red Clay under Leaching Action

Unraveling the Mystery of Water-Induced Loess Disintegration: A Comprehensive Review of Experimental Research

Effect of Soaking Time and Salt Concentration on Mechanical Characteristics of Slip Zone Soil of Loess Landslides

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