基于分布式光纤传感技术的岩土体导热系数测定方法

 以线热源法为基础，阐述基于分布式光纤传感技术的岩土体导热系数测量方法的基本原理。详细介绍测量的基本过程、方法和仪器设备。设计试验模型，对不同含水量情况下的3种岩土体的导热系数进行试验研究。以试验数据为基础，分析光纤温度随时间的变化规律，即随时间变化分为快速和缓慢均匀增长阶段，发现缓慢均匀增长阶段中光纤温度与时间对数具有良好的对数关系，证明该技术可行。同时，研究加热功率大小对导热系数测量的影响，认为在本试验功率范围内，可忽略加热功率对导热系数的影响。在此基础上，研究岩土体含水量对导热系数的影响。研究结果表明，含水量对导热系数具有显著影响，随着含水量的增加，导热系数不断增加，但不同介质的影响程度不同。最后，对该方法进行详细讨论。

MEASURING METHOD OF GEOMATERIAL THERMAL CONDUCTIVITY BASED ON DISTRIBUTED OPTICAL FIBER SENSING TECHNOLOGY

Based on theory of linear heat-source，the basic principle of distributed fiber optical technology for thermal conductivity measurement is described. The measurement process，method and apparatus are introduced. Test model is also built；and the thermal conductivities of three types of geomaterials with different water contents are measured by using distributed fiber optical technology. By means of analyzing test data，the relationship between fiber optical temperature and time is studied. Temperature curve is made up of two segments，i. e. swift growth and gradual uniform growth segments. At uniform growth segment，there is a well logarithm relationship between temperature and time，which approves the feasibility of this method. Through analyzing the effect of heating power on thermal conductivity，the effect of heating power on thermal conductivity can be ignored when the heating power is in the range of this test. Through research of water content¢s effect on thermal conductivity，it is found that water content has dramatic effect on thermal conductivity. Thermal conductivity increases with the increment of water content，but the increasing rates of different media are different. At last，this method is discussed.