西安建筑科技大学学报(自然科学版)

为了研究与电缆载流量相关的土体导热系数,以上海奉贤区某施工现场粉质黏土研究对象,使用KD2 Pro型热特性分析仪,采用热线法测定较广温度范围(5～90℃)和含水率范围内(干燥～饱和状态)重塑土样的导热系数变化,并运用修正的颗粒间接触传热(IPCHT)导热系数模型对试验结果进行了预测分析.结果表明:非饱和上海黏土在较低温度下(≤60℃)的导热系数随其含水率增加的变化幅度相对较小; 较高温度下(>60℃)土样含水率对导热系数的影响较为显著.而对于饱和土样,其导热系数对温度的变化不太敏感.低于90℃时IPCHT模型预测非饱和黏土土样的导热系数效果比较理想,90℃时该模型的预测值和实际值有偏差,经传质增强因子修正后符合工程要求,但对饱和上海黏土导热系数的预测结果偏差较大.研究结果有助于进一步建立饱和上海黏土导热系数模型与电缆载流量的有限元模型.

In order to study the soil thermal conductivity related to the cable current carrying capacity,the silty clay in a construction site in Fengxian District of Shanghai is taken as the research object. In the study,the hot wire method is adopted to measure the change of thermal conductivity of remolded soil samples in a wide temperature range(5-90°C)and moisture content range(dry-saturated)by means of KD2 Pro thermal property analyzer,and the test results are predicted and analyzed by the modified IPCHT thermal conductivity model. The results show that the change range of thermal conductivity of unsaturated Shanghai clay with the increase of its moisture content is relatively small at lower temperature(≤60℃),and the influence of moisture content of soil sample at higher temperature(>60℃)on thermal conductivity is more significant. However,the thermal conductivity of saturated soil is not sensitive to the change of temperature. When the temperature is lower than 90℃,the IPCHT model is ideal for predicting the thermal conductivity of unsaturated clay samples. There is a deviation between the predicted value and the actual value at 90℃,which meets the engineering requirements after the correction of mass transfer enhancement factor,but the prediction result of thermal conductivity of saturated Shanghai clay has a large deviation. The results are helpful to establish the thermal conductivity model of saturated Shanghai clay and the finite element model of cable ampacity.

引言
1 实验材料及方法
2 试验结果及分析
3 不同温度下黏土的导热系数模型预测
4 结论

表1 所使用黏土的物理参数<br/>Tab.1 Physical parameters of clay used

表1 所使用黏土的物理参数
Tab.1 Physical parameters of clay used

图1 颗粒级配曲线
Fig.1 Grain grading curve

图2 KD 2 Pro型热特性分析仪<br/>Fig.2 KD2 Pro thermal property analyzer

图2 KD 2 Pro型热特性分析仪
Fig.2 KD2 Pro thermal property analyzer

图3 导热系数测试过程<br/>Fig.3 Test process of thermal conductivity

图3 导热系数测试过程
Fig.3 Test process of thermal conductivity

图4 土体导热系数随体积含水率的变化<br/>Fig.4 Variation of thermal conductivity of soil with volume moisture content

图4 土体导热系数随体积含水率的变化
Fig.4 Variation of thermal conductivity of soil with volume moisture content

图5 土体导热系数随温度的变化<br/>Fig.5 Variation of thermal conductivity of soil with temperature

图5 土体导热系数随温度的变化
Fig.5 Variation of thermal conductivity of soil with temperature

图6 Δλ随体积含水率和温度的变化<br/>Fig.6 Change of Δλ with volume moisture content and temperature

图6 Δλ随体积含水率和温度的变化
Fig.6 Change of Δλ with volume moisture content and temperature

图7 不同温度下土壤导热系数测定值与预测值的比较<br/>Fig.7 Comparison of measured and predicted values of soil thermal conductivity at different temperatures

图7 不同温度下土壤导热系数测定值与预测值的比较
Fig.7 Comparison of measured and predicted values of soil thermal conductivity at different temperatures

图8 经传质增强因子修正后实测值与预测值的比较<br/>Fig.8 Comparison between measured value and predicted value after mass transfer enhancement factor correction

图8 经传质增强因子修正后实测值与预测值的比较
Fig.8 Comparison between measured value and predicted value after mass transfer enhancement factor correction

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备注

引言

1 实验材料及方法

2 试验结果及分析

3 不同温度下黏土的导热系数模型预测

4 结论

期刊信息