摘要
时域反射仪（ＴＤＲ）是一种利用电磁脉冲方法，根据电磁波在土层中的传播速度测试不同土层 的介电常数，接介电常数值可获不同土类在冻融状态下的未冻水含量和总体积含水量．ＴＤＲ仪可在 野外环境下无破损地测得融土和冻土的液态水含量，尤其是能测出不同负温下冻土中未冻水的变 化．该仪器最适用于测量均质细颗粒土的体积含水量，经与烘干称重法对比，ＴＤＲ仪应用在青藏高 原上不同融土类所测含水量值的误差范围：粉土和细砂为±２．５％，粘土和亚粘土为±３．０％，砂砾石 土和碎石土为±５％．经过反复的野外实践证明，用 ＴＤＲ仪测上层含水量具有简便、快速及稳定等 优点，是值得推广的方法．根据青藏公路沿线８个场地埋置的ＴＤＲ仪和地温仪所获的一个年周期的 水、热资料（１９９７．８～１９９８．７）。
Using electromagnetic pulses, Time- Domain-Reflectometer (TDR) soil moisture is determined by measuring dielectric constant for different soil layers. TDR can be used to determine the liquid water content of soils in unbroken state in field, specially the unfrozen water content of frozen soils in different temperatures. It is more suitable to measure bulk moisture content of finegrained soils. Compared with gravitational method, the accuracy of TDR in determination of bulk moisture content on the Tibetan Plateau is :±2.5% for silt and fine grained sand, ± 3.0% for clay and sandy clay and ±5% for gravel and pebble soils. It can be concluded by repeated field practices that there are many advantages of TDR in determination of soil moisture contents in field, i.e., simple, convenient and quick for field measuring and stable in the measuring results. Based on the moistrue and temperature data (August 1997 to August 1998) from & sites along the Tibetan Highway, the moisture migration in the active layer due to freezing is analyzed in this paper.
出处
《冰川冻土》
CSCD
北大核心
2000年第1期78-84,共7页
Journal of Glaciology and Geocryology
基金
中国科学院冰冻圈动态变化基础研究(KJ-b-2-100)资助
国家与中国科学院青藏高原研究项目!KZ951-A1-204-3-4
中
