Embankments on soft soils effectiveness of berms

Abstract

As part of the GE 4993 course, the following report reviews the results of a parametric study of embankments on soft soils and the effectiveness of berms. Embankments constructed on soft cohesive soils often require berms to achieve acceptable safety factors against rotational failure. Conventional berm design methods, such as Mitchell's and NAVFAC, have been used and been effective in many design situations. However, recent solutions using simple equations derived from slope stability analysis has been suggested for berm design Calculations and analysis show that some designs based on conventional methods would be rejected using this new approach, as they do not meet the minimum required safety factor Recently the Canadian Foundation Engineering manual has recommended use of ultimate limit states design approach in geotechnical engineering However, calculations and analysis show that the use of the limit states design when applied to conventional berm design methods will lead to conservative design. This parametric study draws a comparison between conventional berm design methods and the new suggested approach, and a comparison between the limit states and the working stress design approach.