Research on the Method of Measuring Soil Water Content by Time Domain Reflectometry

Abstract Time domain reflectometry (TDR) can calculate the water content by testing the dielectric constant of the rock and soil medium, but the TDR measurement results under time domain conditions are susceptible to the influence of soil conductivity. This article introduces the basic theory of TDR measurement, then uses the transmission scattering matrix to describe the transmission equation, analyzes the dielectric constant in the frequency domain, simulates the TDR waveform with matlab based on the Debye model, and fits the simulated waveform to the measured waveform, and then according to the simulated waveform The matching degree proves the feasibility of calibrating the dielectric constant of the soil. Taking clay as the measurement object, finally fitting a simulation waveform with a higher degree of matching with the measurement waveform, which proves the feasibility of the method and has certain reference value for the study of the TDR method of measuring soil dielectric constant and water content.