Experimental Study of Soil Texture and Cross River Structures on Depth of Undercutting Hole Induced by Seepage Erosion in River Banks

Abstract

Despite of many researches on bank erosion mechanism, there exists an incomplete understanding of one of the basic mechanisms governing sediment loading to streams which is namely erosion by concentrated lateral, subsurface flow which causes river bank failure after undercutting process and removing sediment into the river. The objective of this research is to study seepage erosion (piping) in river banks in two cases of presence of a cross structure (e.g. drainage pipes or gas transport pipes,…) and without cross structure by measuring the depth of undercutting hole induced by seepage erosion in sand layer with three different grain sizes under different hydraulic gradients in a laboratory flume. The results show that under equal hydraulic gradients length of erosion hole depends on river bank sand layer grain size and presence of cross structures.

Keywords

• bank erosion
• seepage erosion
• piping
• subsurface flow
• depth of undercutting hole
• river bank
• cross structure