Soil-suction measurements for evaluation of vertical water flow at greater depths with a pressure transducer tensiometer

Abstract Periodic suction measurements at greater depths can be carried out in cased boreholes using a temporarily installed pressure transducer tensiometer (Fig. 1). The time needed to reach constant suction values depends upon the tensiometer prestressing and the soil suction, and amounts to about 15 min to 2 1 2 hours according to general experience (Fig. 2). With this technique, requiring relatively low expense for instruments, the hydraulic gradient and — combined with corresponding hydraulic conductivity values — the vertical water flow can be determined at depths up to about 10 m.