The artificial ground freezing (AGF) method is an environmentally friendly ground improvement technique for numerous geotechnical applications. It can be used in fine-grained soils, which may not be efficiently improved via conventional cement-based ground improvement techniques. However, some of the issues hindering the application of the AGF method to fine-grained soils include inefficiency in achieving the target volume of frozen soil and degradation in mechanical properties of the soil after the freezing-thawing process. In this paper, the freezing rate and degradation in strength and stiffness of a clayey silt in South Korea were investigated using field experiments. At two different outlet temperatures (-180°C and -120°C), liquid nitrogen was injected into the freezing pipe to evaluate the freezing rate. A simple equation to estimate the theoretical radial freezing rate was proposed and compared with the experimental results. In addition, a piezocone penetration test (CPTu) and pressuremeter test (PMT) were performed to assess the degradation in strength and stiffness of the soil after the freezing-thawing process. Results of the CPTu, PMT, and laboratory experiments revealed that the degradation in mechanical properties of Korean clayey silt could be attributed to the rearrangement of soil particles.
|Journal of Engineering Mechanics
|Published - 2021 Sept 1
Bibliographical noteFunding Information:
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2019R1A2C2086647).
© 2021 American Society of Civil Engineers.
- Clayey silt
- Degradation in mechanical properties
- Freezing rate
- Liquid nitrogen
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering