Effect of Clay Mica Layer on Stability Analysis of Composite Riverbank using LEM Method

DOI

10.2991/978-94-6463-884-4_55How to use a DOI?

Keywords

Slope stability; Limit Equilibrium Method; Soil layer; Overburden pressure; Toe erosion

Abstract

Alluvial riverbanks predominantly consist of a layered soil profile with varying particle sizes. Typically, on the alluvial riverbank, the lower layer of the composite bank is composed of cohesionless materials like sand and silt, while the top layer of the bank is composed of a clayey-mica soil layer. This paper evaluates the effect of the clay-mica soil layer over the silt-sand soil layer on the slope stability analysis of the riverbank. Analysis was performed considering toe erosion, overburden pressure, pore water pressure, and fluctuations in the water level. In this study, the limit equilibrium method was applied to slope stability analysis for various load conditions. The Morgenstern-Price method and Mohr-Coulomb failure criteria were used to calculate the factor of safety. Water level drawdown was performed from 10 mPWD to 5 mPWD after the flow event, as water level fluctuation can cause riverbank failure. This study showed that riverbanks comprising micaceous clay exhibited higher stability than those with sand and silt layers in the absence of an overburden load and toe erosion. It was found that the riverbank, composed of sand and silt, could withstand more than 60 kPa of overburden pressure when toe erosion does not occur. In the same condition, a clay-mica layer at the top can withstand more than 30 kPa overburden pressure. With 5m scour, 20 kPa overburden pressure caused riverbank failure when the clay-mica layer was considered. Whereas, with the sandy silt and silty sand layer, more than 40 kPa overburden pressure made the riverbank unstable at a depth of 5m of the scoured toe. According to the analysis, the layer composed of clay and mica (30%) exhibited greater resistance to erosion than the layer with sand and silt, particularly in the absence of overburden pressure and toe scour. However, the combined effect of clay, mica (30%), sand, and silt indicated a lower safety factor when an overburden load exists with previous scour. It is hoped that this study will be helpful for planning and designing cost-effective riverbank protection measures when the clay and mica layer is at the top.

Copyright

© 2025 The Author(s)

Open Access

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TY  - CONF
AU  - Md. Shahidul Islam
AU  - Md. Abdul Matin
PY  - 2025
DA  - 2025/11/18
TI  - Effect of Clay Mica Layer on Stability Analysis of Composite Riverbank using LEM Method
BT  - Proceedings of the 8th International Conference on Engineering Research, Innovation, and Education 2025 (ICERIE 2025)
PB  - Atlantis Press
SP  - 460
EP  - 466
SN  - 2352-5401
UR  - https://doi.org/10.2991/978-94-6463-884-4_55
DO  - 10.2991/978-94-6463-884-4_55
ID  - Islam2025
ER  -