DOI QR코드

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A new thermal conductivity estimation model for weathered granite soils in Korea

  • Go, Gyu-Hyun (Department of Civil Engineering, Korean Advanced Institute for Science and Technology) ;
  • Lee, Seung-Rae (Department of Civil Engineering, Korean Advanced Institute for Science and Technology) ;
  • Kim, Young-Sang (Department of Marine and Civil Engineering, Chonnam National University) ;
  • Park, Hyun-Ku (Engineering & Construction Group Civil Engineering Division, Samsung C&T) ;
  • Yoon, Seok (Department of Civil Engineering, Korean Advanced Institute for Science and Technology)
  • 투고 : 2013.06.20
  • 심사 : 2013.11.19
  • 발행 : 2014.04.25

초록

Thermal conductivity of ground has a great influence on the performance of Ground Heat Exchangers (GHEs). In general, the ground thermal conductivity significantly depends on the density (or porosity) and the moisture content since they are decisive factors that determine the interface area between soil particles which is available for heat transfer. In this study, a large number of thermal conductivity experiments were conducted for soils of varying porosity and moisture content, and a database of thermal properties for the weathered granite soils was set up. Based on the database, a 3D Curved Surface Model and an Artificial Neural Network Model (ANNM) were proposed for estimating the thermal conductivity. The new models were validated by comparing predictions by the models with new thermal conductivity data, which had not been used in developing the models. As for the 3D CSM, the normalized average values of training and test data were 1.079 and 1.061 with variations of 0.158 and 0.148, respectively. The predictions became somewhat unreliable in a low range of thermal conductivity values in considering the distribution pattern. As for the ANNM, the 'Logsig-Tansig' transfer function combination with nine neurons gave the most accurate estimates. The normalized average values of training data and test data were 1.006 and 0.954 with variations of 0.026 and 0.098, respectively. It can be concluded that the ANNM gives much better results than the 3D CSM.

키워드

과제정보

연구 과제 주관 기관 : National Research Foundation of Korea, Korea Institute of Construction and Transportation Technology Evaluation and Planning

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  6. Evaluation of calculation models for the thermal conductivity of soils vol.94, pp.None, 2014, https://doi.org/10.1016/j.icheatmasstransfer.2018.02.005
  7. Thermographic analysis of failure for different rock types under uniaxial loading vol.23, pp.6, 2020, https://doi.org/10.12989/gae.2020.23.6.503
  8. A review and evaluation of thermal conductivity models of saturated soils vol.67, pp.7, 2014, https://doi.org/10.1080/03650340.2020.1771315