Mechanical behavior and constitutive model for loess samples under simulated acid rain conditions

Area of Science:

• Geotechnical Engineering
• Environmental Science
• Soil Mechanics

Background:

• Acid rain, primarily sulfuric and nitric acid solutions, degrades soil mechanical properties.
• This degradation poses risks to the safety and integrity of soil engineering structures.
• Understanding the impact of acid rain on soil is crucial for sustainable infrastructure development.

Purpose of the Study:

• To investigate the effects of sulfuric acid rain on the mechanical properties of loess soil.
• To analyze the microstructural changes in loess due to acid rain exposure.
• To develop and validate a chemical-mechanical model for loess under acid rain conditions.

Main Methods:

• Simulated acid rain with pH values of 5.0, 4.0, and 3.0.
• Conducted triaxial compression tests on saturated loess samples.
• Utilized scanning electron microscopy (SEM) to examine microstructural evolution.

Main Results:

• Acid rain increased loess porosity and altered pore distribution and grain contacts.
• Decreased pH values led to reduced peak deviatoric stress and volumetric contraction.
• Shear strength parameters of loess were diminished with increasing acid rain severity.

Conclusions:

• Sulfuric acid rain significantly deteriorates the mechanical behavior of loess.
• Microstructural changes are directly linked to the observed reduction in soil strength.
• The established chemical-mechanical model accurately predicts loess behavior under acid rain, aiding in risk assessment.