Computation of critical tractive stress of scaling sizes in non-uniform sediments

Abstract

Relationships were proposed expressing the ratio of dimensionless critical tractive stress (CTS) of a particular size fraction to the dimensionless CTS of scaling/representative size in sediment mixtures, as a function of their respective size ratios. The predictor of dimensionless CTS of scaling size is a mandatory requirement to predict the CTS of a particular size fraction of a sediment mixture. Data of the CTS for non-uniform sediments from the previous investigations have been analysed to check the adequacy of these predictors. An equation is proposed to predict the CTS of scaling sediment size in terms of Kramer's uniformity coefficient. The performance of the proposed relationship was also tested by comparing observed and predicted results with independent laboratory and field data. The proposed relationship performs better for both unimodal and bimodal grain size distributions.

Keywords:

• Bimodal
• critical tractive stress
• non-uniform sediment
• scaling size
• sediment

Acknowledgement

The authors are thankful to the Department of Science and Technology (DST), New Delhi, Government of India, for providing funding for the Research Project Erosion of non-uniform unimodal and bimodal sediments.

Additional information

Notes on contributors

Prem Lal Patel

IAHR Member

Prakash Devidas Porey

IAHR Member