Threshold for initiation of motion of unimodal and bimodal sediments

Experimental data, obtained from previous studies, on Critical Tractive Stress （CTS） of non-uniform sediments, have been used to verify the adequacy of existing relationships for CTS of non-uniform bimodal sediments. Keeping in view the performance of such relationships, a new relationship for computation of dimensionless CTS of individual size fraction of non-uniform unimodal and bimodal sediments has been proposed in the form of power law. The coefficient and exponent of the proposed power law have been empirically correlated with sediment characteristics for available sediment data. The proposed relationship has been validated with independent flume and field data to assess their applicability for unimodal and bimodal sediments.