nalysis of Air Heating Du ow through Ground Passages

$0 day period of below freez-eratures, air was circulated an underground tunnel. er onstant airflow rate, rock and temperatures were observed every hours at instrumented stations ng the tunnel from the portal intake outlet. Tunnel iceform-and the depth of rock temp-re cooling in from the tunnel ce were also recorded. The data analysed to establish the heat energy transfer characteristics een the circulating air and the. he day to day surface climatic anges were recorded and correlate