Geomechanics and Engineering

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Mechanism of strength damage of red clay roadbed by acid rain

  • Guiyuan Xiao (Key Laboratory of Geotechnics of Guangxi, Guilin University of Technology) ;
  • Jian Wang (Key Laboratory of Geotechnics of Guangxi, Guilin University of Technology) ;
  • Le Yin (Guangxi Zhuang Autonomous Region company of China National Tobacco Corporation ) ;
  • Guangli Xu (College of Engineering, China University of Geosciences) ;
  • Wei Liu (Shiyan City Natural Resources and Planning Bureau)
  • Received : 2023.04.26
  • Accepted : 2023.06.23
  • Published : 2023.09.10
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Abstract

Acid rain of soils has a significant impact on mechanical properties. An X-ray diffraction test, scanning electron microscope (SEM) test, laser particle size analysis test, and triaxial unconsolidated undrained (UU) test were carried out in red clay soils with different compaction degrees under the effect of different concentrations of acid. The experiments demonstrated that: the dissolution effect of acid rain on colluvium weakened with the increase in the compacting degree under the condition of certain pH values, i.e., the damage to the structure of red clay soil was relatively light, where the number of newly increased pores in the soil decreased and the agglomeration of soil particles increased; for the same compacting degree, the structural gap decreased, and the agglomeration increased with the increase in the pH value (acidity decreases) of the acid rain; the dissolution rate of Si, Al, Fe, and other elemental minerals and cement in red clay soil was found to be higher under the effect of acid rain, in turn destroying the original structure of the soil body and producing a large number of pores. This is macroscopically expressed as the decrease of the soil cohesion and internal friction angle, thereby reducing the shear strength of the soil body.

Keywords

Acknowledgement

The authors thank Mr. Yukai fang for assisting with the SEM measurements.

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