Testing Study Concerning the Effect of Temperature on the Thermal Conductivity of Granite and Sandstone

Thermal conductivity is an uppermost characteristic parameter in temperature field analysis, and it will influenc the distribution of temperature field directly in surrounding rock of tunnel. In order to study the effect of temperature on thermal conductivity, the thermal conductivity tests for granite and sandstone are conducted at various temperature level(28 similar to 62 degree celsius). Based on the test results, the effect of temperature on the thermal conductivity of granite and sandstone are preliminarily analyzed. The testing results show that the thermal conductivity of granite decreases slowly with increasing of temperature, and there is a negative linear relationship between the thermal conductivity of granite and temperature ( lambda = 3.1581-0.0043T). Whereas, the thermal concuctivity of sandstone has no obvious change basically with increasing of temperature. So the influence of temperature on thermal conductivity and its induced change of stress field should be considered in accurate analysis of the distribution of stress field and temperature field in surrounding rock of tunnel.