Slide Repair and Drainage Improvements

Background

This section of track on the west side of Minot, ND, was built in the late 1800s as part of the Great Northern Railway and had not shown any signs of instability until the mid-2010s following above average precipitation and urbanization of the watershed.

A 500-foot-long by 35-foot-high slide had developed and slid down to the base of the railway. This was part of a vital link of BNSF Railway’s transcontinental infrastructure, connecting Chicago to Seattle.

BNSF employed Houston Engineering, Inc. (HEI) to resolve the issue before conditions worsened and something catastrophic occurred, such as a rail blockage or, worse yet, a derailment.

The Project

Work began with a topographic survey, geotechnical exploration (with the support of a geotechnical subconsultant), and hydrologic assessment of the area. Drainage was suspected to be a contributing factor. Laboratory testing and slope stability analysis determined that a prudent solution would include a combination of excavation of the disturbed soils, back sloping, engineering fill, and drainage improvements.

More than 4,000 cubic yards of fractured granite rock was imported, and a tiled drainage system was constructed to stabilize the slope. A concrete-lined channel was constructed to convey stormwater coming away from the slide area and under the US 2 overpass.

The concrete-lined channel was necessary for increased flow capacity in a confined area. Besides utility relocations and coordination, HEI also prepared legal documents and coordinated with the owner of a neighboring retirement home to purchase property and acquire construction easements on behalf of BNSF. HEI also provided the bidding and construction management services. The project was completed in 2017 at a price of approximately $1.5 million.