A tensiometer is used to measure a compacted soil in the field that has a matric suction of 200 kPa under atmospheric conditions. The pore-water pressure measurement in the tensiometer reaches -99 kPa and suddenly increases to zero. Briefly explain the problem encountered in this measurement.
A tensiomater is used to measure a soil specimen in the labaratory that has a constant matric suction of 30 kPa under atmospheric conditions. In the beginning the pore-water pressure measurement in the tensiometer reaches -30 kPa, but after a few days the meausrement drifts to a higher pore-water pressure. Briefly explain the problem encountered in this measurement.