Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States
Thermal properties are important for featuring the water-heat transfer capacity of soil. They are also key to many processes in earth sciences, such as the land surface processes and ecological and geoenvironmental dynamics and their changes in permafrost regions. With loose and porous structures, t...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2021-01-01
|
| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2021/7566669 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832561566361321472 |
|---|---|
| author | Ruixia He Ning Jia Huijun Jin Hongbo Wang Xinyu Li |
| author_facet | Ruixia He Ning Jia Huijun Jin Hongbo Wang Xinyu Li |
| author_sort | Ruixia He |
| collection | DOAJ |
| description | Thermal properties are important for featuring the water-heat transfer capacity of soil. They are also key to many processes in earth sciences, such as the land surface processes and ecological and geoenvironmental dynamics and their changes in permafrost regions. With loose and porous structures, the organic matter layer in soil strata substantially influences soil thermal conductivity. So far, thermal conductivity of mineral soils has been explored extensively and in depth, but there are only limited studies on that of organic soils. In this study, influences of soil temperature, soil moisture saturation (SMS), and soil organic matter (SOM) content on soil thermal conductivity were analyzed on the basis of laboratory experiments on the silt-organic soil mixtures of varied mixing ratios. Results show that soil thermal conductivity declines slowly with the lowering temperatures from 10 to 0°C; however, it increases and finally stabilizes when temperature further lowers from 0 to -10°C. It is important to note that thermal conductivity peaks in the temperature range of -2~0°C (silty and organic-poor soil) and -5~0°C (organic-rich soil), possibly due to phase changes of ice/water in warm permafrost. Under both thawed and frozen states, soil thermal conductivity is positively related with SMS. However, with rising SOM content, the growth rate of soil thermal conductivity with SMS slows gradually. Given the same SMS, soil thermal conductivity declines exponentially with increasing SOM content. Based on the experimental and theoretical analyses, a new empirical computational formula of soil thermal conductivity is established by taking into account of the SOM content, SMS, and soil temperature. The results may help better parameterize in simulating and predicting land surface processes and for optimizing frozen soil engineering designs and provide theoretical bases for exploring the dynamic mechanisms of environmental changes in cold regions under a changing climate. |
| format | Article |
| id | doaj-art-60de79952d5745cbb612199ed504a0c2 |
| institution | Kabale University |
| issn | 1468-8115 1468-8123 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geofluids |
| spelling | doaj-art-60de79952d5745cbb612199ed504a0c22025-02-03T01:24:42ZengWileyGeofluids1468-81151468-81232021-01-01202110.1155/2021/75666697566669Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen StatesRuixia He0Ning Jia1Huijun Jin2Hongbo Wang3Xinyu Li4State Key Laboratory of Frozen Soils Engineering and Da Xing’anling Observation and Research Station of Frozen-Ground Engineering and Environment, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 73000, ChinaSchool of Civil Engineering, Harbin Institute of Technology, Harbin 150090, ChinaState Key Laboratory of Frozen Soils Engineering and Da Xing’anling Observation and Research Station of Frozen-Ground Engineering and Environment, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 73000, ChinaSchool of Civil Engineering, Tianshui Normal University, Tianshui, Gansu 741001, ChinaSchool of Civil Engineering, Harbin Institute of Technology, Harbin 150090, ChinaThermal properties are important for featuring the water-heat transfer capacity of soil. They are also key to many processes in earth sciences, such as the land surface processes and ecological and geoenvironmental dynamics and their changes in permafrost regions. With loose and porous structures, the organic matter layer in soil strata substantially influences soil thermal conductivity. So far, thermal conductivity of mineral soils has been explored extensively and in depth, but there are only limited studies on that of organic soils. In this study, influences of soil temperature, soil moisture saturation (SMS), and soil organic matter (SOM) content on soil thermal conductivity were analyzed on the basis of laboratory experiments on the silt-organic soil mixtures of varied mixing ratios. Results show that soil thermal conductivity declines slowly with the lowering temperatures from 10 to 0°C; however, it increases and finally stabilizes when temperature further lowers from 0 to -10°C. It is important to note that thermal conductivity peaks in the temperature range of -2~0°C (silty and organic-poor soil) and -5~0°C (organic-rich soil), possibly due to phase changes of ice/water in warm permafrost. Under both thawed and frozen states, soil thermal conductivity is positively related with SMS. However, with rising SOM content, the growth rate of soil thermal conductivity with SMS slows gradually. Given the same SMS, soil thermal conductivity declines exponentially with increasing SOM content. Based on the experimental and theoretical analyses, a new empirical computational formula of soil thermal conductivity is established by taking into account of the SOM content, SMS, and soil temperature. The results may help better parameterize in simulating and predicting land surface processes and for optimizing frozen soil engineering designs and provide theoretical bases for exploring the dynamic mechanisms of environmental changes in cold regions under a changing climate.http://dx.doi.org/10.1155/2021/7566669 |
| spellingShingle | Ruixia He Ning Jia Huijun Jin Hongbo Wang Xinyu Li Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States Geofluids |
| title | Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States |
| title_full | Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States |
| title_fullStr | Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States |
| title_full_unstemmed | Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States |
| title_short | Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States |
| title_sort | experimental study on thermal conductivity of organic rich soils under thawed and frozen states |
| url | http://dx.doi.org/10.1155/2021/7566669 |
| work_keys_str_mv | AT ruixiahe experimentalstudyonthermalconductivityoforganicrichsoilsunderthawedandfrozenstates AT ningjia experimentalstudyonthermalconductivityoforganicrichsoilsunderthawedandfrozenstates AT huijunjin experimentalstudyonthermalconductivityoforganicrichsoilsunderthawedandfrozenstates AT hongbowang experimentalstudyonthermalconductivityoforganicrichsoilsunderthawedandfrozenstates AT xinyuli experimentalstudyonthermalconductivityoforganicrichsoilsunderthawedandfrozenstates |