含水量与孔隙率对土体热导率影响的室内实验

为建立热导率与影响因素间的确定性关系和推算公式,需要严格的实验,即研究某一影响因素时应保持其他因素不变.在严格控制其他各影响因素的情况下,分别研究了土体热导率随含水量(保持孔隙率、土样成分等不变)及随孔隙率(保持含水量、土样成分等不变)的变化规律,在此基础上再对影响因素的综合影响进行研究.并从微观的角度分析土体热导率的变化规律,研究其内在传热机制.分析发现,土样种类不同,热导率随含水量及孔隙率的变化规律也不同,同时还发现土体内部粘粒含量是表征热导率递变速率发生明显变化的重要因素.给出了土体热导率的经验公式,将该公式计算值与工程土体的实验值进行对比后发现,两者间相对误差较小,该公式可直接应用于实际工程.

Laroratory on influences of moisture content and porosity on thermal conductivity of soils

In o rder to build precise r elat ionship betw een thermal conductivity and influencing facto rs, st rict exper iment s ar e required. Other factors sho uld be kept constant w hile the ef fect of an inf luencing factor is examined. T he ef fect s o f moisture content ( w ith constant por osity and composit ion o f so ils) and poro sity ( w ith co nstant moistur e content and compo sit ion of soils) w ere examined individually . Based on these result s, the g eneral relation betw een thermal co nductiv ity and moisture co ntent and porosity w as analyzed at the micro level. And the heat t ransfer mechanism of soils w as studied to ex plain the present resul ts. It is fo und that the so il s of dif ferent ty pe fo llow dif ferent r elat ion, and that the content of clay part icles is a very important factor to illust rate the obv io us chang e o f thermal conductivity . T he empirical relat io ns were pr esented, for predict ing the conduct ivity of all above soils, and their ef f iciency w as established by comparing with the exper imental result s of soils in eng ineer ing .