Streambank Stability

Erosion of alluvial soils along the Ohio River is a matter of increasing concern to riparian landowners and commercial interests. One mechanism by which erosion of alluvial streambanks takes place is by sliding wedge failures of upper bank layers. Results of a study are presented in which the sliding wedge mechanism was investigated for Ohio River banks. Streambanks were assumed to fail by sliding along sand partings underlying cohesive upper layers. Results of computer wedge stability analyses indicated that bank stability is most sensitive to the depth of water present in tension cracks behind the face of the bank. Other factors found to be important to wedge stability are the effective angle of internal friction of the sand seam underlying the cohesive sliding wedge and the unit weight of the cohesive wedge. The importance of tension crack formation on wedge stability of multi-layered river banks was also evaluated.