Experiments to simulate the salinisation process of loess under a dynamic water cycle

Area of Science:

• Geotechnical Engineering
• Environmental Science
• Soil Science

Background:

• Loess salinisation threatens ecological stability and sustainable development in the Loess Plateau.
• Understanding salt solution impacts on loess is vital for effective land management.

Purpose of the Study:

• To investigate the effects of salt solution concentration, type, and soaking duration on loess physico-mechanical properties.
• To analyze the microstructural changes in loess due to salt solution interaction.

Main Methods:

• Utilized custom-built salt solution-loess dynamic cyclic erosion equipment for soaking tests.
• Performed various tests to assess changes in shear strength, compressibility, cohesion, and internal friction angle.
• Examined the microstructural evolution and water-loess chemical interactions.

Main Results:

• Shear strength initially decreased then increased; compressibility initially increased then declined with increasing salt solution concentration (SSC).
• After 7 days, cohesion remained stable, while the internal friction angle increased with SSC.
• Salt solutions can decelerate loess disintegration, with longer soaking times shortening this duration.

Conclusions:

• Salt solution interactions, particularly clay mineral exchange with iron and aluminium ions, are key to water-loess chemical interactions.
• Findings provide guidance for preventing and treating salinised loess in Northwest China and similar regions.
• The study highlights the complex effects of salinisation on loess, crucial for ecological preservation.