Engineering Geology of Interstate Highway 94 Underpass at Northern Pacific Railway, Fargo, North Dakota
Published:January 01, 1968
Gordon L. Bell, 1968. "Engineering Geology of Interstate Highway 94 Underpass at Northern Pacific Railway, Fargo, North Dakota", Engineering Geology Case Histories Number 6, George A. Kiersch
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Construction of four-lane Interstate Highway 94, at the Streeter Branch of Northern Pacific Railway south of Fargo, North Dakota, encountered excessive ground water in silty sand. The underpass required special excavation with two stages of well points where “quicksand” was encountered in an abandoned stream channel within sediments of ancient Lake Agassiz.
Exploration drilling of 11 test holes indicated as much as 78 feet of “quicksand” under the structure site. Discovery of these subsurface conditions resulted in several construction changes including the use of well points, vertical sand drains, and special filter-sand-encased subdrains discharging into a lift station.
Special excavation during abnormally rainy weather was accomplished with the aid of a second well-point system along the median below the 896-foot level in the buried channel system.
The area was successfully excavated and drained to a lift station. The Northern Pacific Railway bridge and the twin highway were completed. The concrete pavement has remained stable under constant use since November 1960.
This is an example of the use of well points in stabilizing saturated soils for highway foundations.
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Engineering Geology Case Histories Number 6
This is the sixth volume in the Case History series of the Division on Engineering Geology of the Geological Society of America, initiated in 1957. Each succeeding volume has enjoyed increasing acceptance as an aid to the practicing geologist and engineer, student, and teacher, alike. This volume is a collection of general case histories on dams, tunnels, highways, and underground construction. Indeed, the Baldwin Hills reservoir failure is another in a long list of cases which demonstrate why the geologic environment, features, and circumstances are of major concern to engineering works.