海底表层土导热系数变化规律的试验研究

Experimental study on variation of thermal conductivity of superficial submarine soils

基于热探针法原理,测试了在杭州湾以东陆架区取得的28个海底表层柱状样0.2、1.0和1.8 m处的导热系数,结合激光粒度分析结果,比较了研究区6种土导热系数的大小,发现含砂量大于10%的粗粒土拥有较大的导热系数。土质类型相同时,含水量和干密度对其导热系数影响显著。杭州湾沉积区、混合沉积区,陆架砂质沉积区表层土导热系数的平均值分别是:1.25、1.45和1.46 W·m^-1·K^-1,呈现出由近岸向外海增大的趋势。而土样导热系数在垂向的变化表明:水深、埋深等空间分布因素对海洋土的热物性没有直接影响。

From the continental shelf at the east of Hangzhou Bay,28 sample columns were acquired.The thermal conductivities of soils at different depths(0.2 m,1.0 m and 1.8 m)from these cores were tested by thermal probe.Correspondingly,particle size of the soils were also tested.Through the comparison between six kinds of soils in the study area,It was found that those with higher sand content(>10%)have bigger thermal conductivities.Besides,water content and dry density have significant effect on thermal conductivities of certain type of soil.Average value of thermal conductivity for superficial soils in Hangzhou Bay area,mixed deposit area and shelf sandy area are respectively 1.25 W·m^-1·K^-1,1.45 W·m^-1·K^-1 and 1.46 W·m^-1·K^-1,which indicates that thermal conductivities increase from the coast to open waters.On the other hand,vertical variation of thermal conductivities shows that spatial factors including water depth and buried depth have no direct effect on the thermophysical properties of seabed soils.