Extension and functional properties for TDR measurement application

本研究的目的是建立TDR测量的新应用，并阐明其功能特性。在本报告中，包括三个主要研究课题。(1)研制了宽3 cm的电路板上8个探头组成的多探头测头，并对其性能进行了研究。利用MWP对砂质土和腐解花岗岩土在蒸发过程中的剖面进行了测量，发现两者的剖面有明显的差异。(2)TDR技术在水库泥沙淤积监测中的适用性。介电常数与沉积层高度呈线性关系，受水的电导率影响较小。(3)对TDR探测淡水和咸水边界进行了研究。TDR波形的分析使高精度地估计边界层成为可能。通过测量，我们还发现淡水的电导率也可以被评估。

The purpose of the present study was to establish new applications of TDR measurement and to clarify their functional properties. In this report, three major research topics are included. (1) A multi TDR probe (MWP), having 8 probes in the electric board of 3-cm wide, was developed and properties of the MWP were investigated to measure water content profile near soil surface. The measurements of the profile conducted during evaporation process for sand and decomposed granite soil by using the MWP revealed clear difference of the profile between the soils. (2) Applicability of TDR technique to the monitoring of soil deposit level in water reservoir. A linear relationship between dielectric constant and the deposit level was found with minor impact of electrical conductivity of water. (3) The detection of boundary between fresh- and salt-water using TDR was examined. The analysis of TDR wave form made it possible to estimate the boundary level with high accuracy. With the measurement, we also found that the electrical conductivity of the fresh water can be also evaluated.