CGRG Bibliography of Canadian Geomorphology
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Author : Burgess, M.M.; Nixon, J.F.; and Lawrence, D.E.
Date : 1998
Title : Pipe and soil movements in permafrost terrain, Norman Wells pipeline
Publication : American Geophysical Union.1998 Fall Meeting. December 6-10, 1998. San Francisco, California [abstract].
Issue :
Page(s) :
Abstract
The buried Norman Wells oil pipeline has been operating since 1985 in discontinuous permafrost terrain of northwestern Canada. The small diameter ambient temperature line, the first of its kind in permafrost terrain in North America, was designed to accommodate up to 0.8 m of thaw settlement in mineral soils and 1.2 m of settlement in organic terrain. Oil is chilled to near ground temperatures before entry at Norman Well, N.W.T. into the 869 km long line. Collaborative government-industry research and monitoring at a series of instrumented sites along the route has documented cumulative soil and pipe movements in response to the thermal disturbance from right-of-way clearing and 13 years of pipeline operation. Annual (or less frequent) measurements have indicated that pipe settlements have reached design values in several areas along the route, although there is no evidence of excessive straining of the pipe at these locations. Thaw strains in the underlying soils are in the range of 20\%. A study of seasonal pipe movements in response to the annual freeze-thaw cycle began in 1994. Detailed pipe elevation surveys have shown that seasonal heave and settlement of the pipe of up to 22 cm occurs. At one location, the pipeline has experienced uplift of over 1 m and exposure above the ground surface. Seasonal thermal cycles and low density thawed soils likely contributed to this behaviour.
Bibliography of Canadian Geomorphology