Thermo-mechanical enhancement and fissure-induced weakening of thermal conductivity in Shanghai mucky clay
Frozen soil thermal conductivity is the core parameter of thermodynamic analysis in frozen soil engineering, and its variation pattern directly influences freezing temperature field prediction precision and freezing curtain design optimization. Taking Shanghai mucky clay as a representative case, th...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
|
| Series: | Results in Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590123025023643 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Frozen soil thermal conductivity is the core parameter of thermodynamic analysis in frozen soil engineering, and its variation pattern directly influences freezing temperature field prediction precision and freezing curtain design optimization. Taking Shanghai mucky clay as a representative case, the thermal conductivity variations under freeze-thaw conditions were systematically investigated, with particular emphasis on thermo-mechanical-fracture (temperature-stress-fissure) coupling effects. Experimental evidence indicated that during the critical phase transition stage (-0.5 °C to -1 °C), clay displayed a restrained thermal conductivity elevation, while thermo-mechanical coupling effects impeded its rapid growth caused by fissure development. Conversely, during the positive freezing stage (-5 °C to -30 °C), a substantial rise in clay's thermal conduction capacity was observed, facilitated by thermo-mechanical interactions. After thawing, the thermal conductivity exhibited a slow increase. Microscopic analysis indicates that thermo-mechanical coupling influences thermal conductivity by altering soil particle contact and unfrozen water film connectivity. Applied stress usually promotes thermal conductivity by improving particle contact, whereas fracture disrupts heat transfer by disrupting the contact network at -0.5 °C to -1 °C. The unfrozen water film is less connected during the phase transition stage due to the creation of fissures, and the thermal conductivity increases faster during the positive freezing stage due to the completely connected state. During freezing, ice formation (increasing thermal conductivity) and fissure development (decreasing thermal conductivity) lead to a complex nonlinear evolution of thermal conductivity. These results provide a fundamental benchmark for the thermal properties of mucky clay soils and provide important insights for optimizing frozen soils where crack-sensitive soils are prevalent. |
|---|---|
| ISSN: | 2590-1230 |