Adam Ries

Date of Award


Document Type

Senior Project

Degree Name

Bachelor of Science (BS)


Geological Engineering

First Advisor

Lance Yarbrough


This senior engineering design project analyzes and remediates a slope failure that occurred in Bismarck, North Dakota. The failure emerged along River Road on the Eastern bank of the Missouri River less than a half mile north of the Burlington Northern Santa Fe Railroad Bridge. The failure took place the week of June 28, 2009 and forced closing of River Road until late fall. A local business was forced to close and traffic was affected throughout the summer.

Elevation and geological data was used to reconstruct the pre-failure slope. The slope was analyzed using a slope stability program, Slope 5.0, by Rocscience. The calculated factors of safety confirmed the instability of the slope.

Several remediation methods were considered such as benching, removal of material, ‘H’ piles, and soils nails. The methods were analyzed using Slope 5.0. The proximity of the river and need for the road were the greatest constraints in considering a method of remediation. Benching created a stable slope, but the small area and steep slope would be difficult to navigate with heavy machinery. Removing material from the head of the slope is not acceptable because the area needs to remain the same to harbor River Road and the adjacent bike path. Soil nailing is possible for the slope, but the failure planes are relatively deep and the nails did not provide the necessary stability. ‘H’ piles provided the best remediation. Factors of Safety were all over 1.3 for the calculated methods. The piles could be easily installed at the top of the road. 50 foot piles spaced three and one half feet apart intersected almost all of the planes of failure.

It was found that ‘H’ piles were the most effective remediation method considering the constraints of the slope. The remediation is to take place as soon as possible to relieve stress on local traffic and businesses.