广西红黏土热物理特性及影响因素试验研究

Experimental study on thermal properties of red clay in Guangxi province and its influence factors

结合矿物组成分析,通过室内试验对广西4种红黏土的热物理特性从土质学角度进行了深入研究,探讨了红黏土的热特性参数与各影响因素之间的关系。研究结果表明:当土体干密度保持不变,红黏土的热导率、比热容随体积含水率的增加而线性递增;热导率变化曲线存在临界含水率点,土体含水率低于该点时,热导率呈线性急剧增加,反之,热导率增长缓慢,趋于稳定;热扩散率以临界含水率点为界,先随含水率的增大而递增,到达临界含水率后随含水率的增加而递减,整体呈抛物线的变化趋势;当土体含水率保持不变,红黏土的热导率、比热容、热扩散率均随干密度的增加而线性递增;红黏土矿物成分中的石英含量对土体的热导率具有显著影响,石英含量与热导率的增长速率呈正相关的关系。

By analyzing their mineral compositions, the thermo-physical properties of 4 kinds of red clay in Guangxi Province are studied from the perspective of soil mechanics. The relationship between the thermal parameters and their impact factors also discussed. The results show that the thermal conductivity and specific heat capacity both increase linearly with the increasing water content when the dry density of soil samples keeps the same value. There is a critical water content point on the change curves of thermal conductivity. The thermal conductivity increases sharply in a line with the increasing water content when the water content is lower than the critical point. Conversely, the thermal conductivity increases slowly and tends to a stable constant. The thermal diffusivity increases with the water content when the water content is lower than the critical value. However, the thermal diffusivity decreases with the water content when the water content is larger than the critical value. The change curves of thermal diffusivity are shown as parabolic shape. It is also found that the thermal conductivity, specific heat capacity and thermal diffusivity show a linear increase with the dry density when the soil water content keeps the same value. Finally, the quartz content of mineral composition of red clay has obvious impact on its thermal conductivity. The increase rate of thermal conductivity of red clay is positively related with its quartz content.