Calibration of Thermal Conductivity Sensors for Measuring Soil Suction
The accuracy of suction measurements using thermal conductivity sensors is dependent upon their calibration. Therefore, a calibration study was undertaken by using a modified, commercially available, pressure plate extractor. The experimental setup along with the calibration procedure are described. Typical calibration results are presented. In general, results showed reasonable agreement between the calibration curve determined in this study compared to those provided by the manufacturer for matric suction ranging from 0 to 175 kPa. However, large deviations in the calibration curves were observed at suctions above 175 kPa. The sensors were found to be quite sensitive to the changes in matric suction in the range of 0 to 175 kPa. For matric suction above 175 kPa, the sensitivity of the sensor is reduced.