Measurement and Prediction of Undisturbed Underground Temperature Distribution

The underground temperature distribution and variation are important for the development and utilization of shallow geothermal energy and underground space. In this paper, a remote ground temperature monitoring system was established in Chongqing, located in southwest China and the ground temperature distribution and its variation with seasons of the 100m underground depth was measured from June 2010 to June 2011. The results show that, in the typical geo-structure of Chongqing, the variational ground temperature zone is from 0m to 10m, where the ground temperature is strongly affected by the change of ambient temperature. Below 11m depth, the ground temperature does not change with seasons, i.e., it is the constant ground temperature zone. In the constant temperature zone below 40 meter depth, the geothermal gradient is about 0.02°C/m. Baggs’s empirical formula was applied to predict the ground temperature distribution history at different ground depths. The results show a good agreement with the measured data.