ESTIMATION OF CRITICAL SHEAR STRESS OF SEDIMENT USING ROTATIONAL VISCOMETER

Abstract

 The critical shear stress of the sediment is an important parameter that determines the transportation of the sediment. However, it is difficult to carry out experiments on a large number of samples because a large-scale experimental device and a large number of samples are required to measure the critical shear stress of the sediment. On the other hand, in the measurement using a rotational viscometer, the result obtained is the yield value. However, the experimental equipment is not large, the operation is simple, and the amount of sample required for the experiment is about 200 mL. In this study, in order to establish a simple method for measuring the critical shear stress of sediment, the relationship between the yield value obtained from the rotational viscometer and the critical shear stress obtained from the circulating water tank were investigated using various type of sediment.

 From the experimental results, it was found that there is a correlation between the yield value and the critical shear stress. Moreover, the relationship between the yield value and the water content of the sediment can be expressed by water retention. From these results, the relationship between the water content of sediment and the critical shear stress can be estimated by measuring the water content after centrifugation, which is an index of water retention.