Performance of a 48-in. Warm-oil Pipeline Supported on Permafrost

1973 ◽  
Vol 10 (2) ◽  
pp. 282-303 ◽  
Author(s):  
R. K. Rowley ◽  
G. H. Watson ◽  
T. M. Wilson ◽  
R. G. Auld
Keyword(s):  
Thermal Regime ◽  
Support Systems ◽  
Ground Surface ◽  
Test Site ◽  
Two Dimensional ◽  
Foundation Soil ◽  
Climatological Data ◽  
Oil Pipeline ◽  
Pipe Line ◽  
And Performance

An experimental pipeline loop, 2000 ft (609.8 m) long and 4 ft (1.22 m) in diameter, was constructed on the Mackenzie Valley Pipe Line Research Limited test site near Inuvik, N.W.T. Oil at 160 °F (71 °C) was circulated through the loop from February 1971 until January 1972 and performance of the continuous gravel berm and intermittent pile bent support systems and ice-rich permafrost foundation monitored.Instrumentation was placed on and around the pipeline to measure settlement and temperature. Site climatological data were also compiled. Settlement and other movements were monitored by periodically taking elevations at the ground surface and on survey rods attached directly to the pipe. Temperatures were measured using both resistance thermal device (R.T.D.) and thermistor type sensing elements. Measured changes in the foundation soil thermal regime were compared with performance as predicted by a two-dimensional thermal simulator model.The observed pipeline loop performance is discussed and compared with predictions for both foundation thawing and settlement. Applicability of the thermal simulator model used and the support piling behavior is also discussed.

scholarly journals Instrumentation Around a Warm Oil Pipeline Buried in Permafrost

1973 ◽  
Vol 10 (2) ◽  
pp. 227-245 ◽  
Author(s):  
W. A. Slusarchuk ◽  
G. H. Watson ◽  
T. L. Speer
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Surface ◽  
Test Facility ◽  
Sensing Element ◽  
Oil Pipeline ◽  
Pore Pressures ◽  
Pipe Line

A section of an uninsulated pipeline, 90 ft (27.4 m) long and 2 ft (0.61 m) in diameter, was buried in ice-rich permafrost at the Mackenzie Valley Pipe Line Research Limited Inuvik Test Facility. Oil at 160 °F (71 °C) was circulated through the pipe from July 1971 to January 1972 causing a thaw bulb to develop around it.Instrumentation was placed around the pipe to measure temperature, settlement, and pore-water pressure. Temperatures near the ground surface and at depth were measured using thermistors as the sensing element. Settlement was monitored by spiral foot gauges and by taking elevations at the ground surface and on rods welded to the pipe. Pore pressures were measured by gas-operated and Casagrande-type piezometers. Selection, fabrication, and installation of this instrumentation are discussed.

Norman Wells pipeline permafrost and terrain monitoring: geothermal and geomorphic observations, 1984–1987

1990 ◽  
Vol 27 (2) ◽  
pp. 233-244 ◽  
Author(s):  
M. M. Burgess ◽  
D. G. Harry
Keyword(s):  
Thermal Regime ◽  
Monitoring Program ◽  
Surface Erosion ◽  
Control Structures ◽  
Oil Pipeline ◽  
Right Of Way ◽  
And Performance ◽  
The Right ◽  
Program Components

A long-term permafrost and terrain research and monitoring program along the 869 km buried oil pipeline between Norman Wells, Northwest Territories, and Zama, Alberta, has been undertaken by the Geological Survey of Canada, in cooperation with the Department of Indian and Northern Affairs Canada. The two main program components are (1) the detailed quantification of changes in the geothermal regime and geomorphic conditions at instrumented monitoring sites and (2) general observations of terrain conditions and performance along the pipeline route. Pipeline operation commenced in April 1985. Observations during the first 2.5 years of pipeline operation indicate that, as expected, the pipe thermal regime and ground thermal regime have not yet stabilized in response to construction and operation. Warming trends in both mean annual pipe temperature and mean annual right-of-way ground temperature have occurred. Surface settlement in permafrost terrain is ongoing in the pipe trench as well as on the remainder of the right-of-way. Surface erosion has occurred, particularly at stream crossings and on low-angle slopes lacking erosion control structures. Key words: pipeline, permafrost, thermal regime, thaw settlement, surface erosion, instrumentation, Norman Wells, Mackenzie Valley, Canada.

Design and Construction Challenges of a Roped Insulated Pipeline

2020 ◽  
Author(s):  
Neetu Prasad ◽  
Graeme King ◽  
Arfeen Najeeb
Keyword(s):  
Ground Surface ◽  
Large Temperature ◽  
Worst Case ◽  
Oil Pipeline ◽  
Upheaval Buckling ◽  
Timely Completion ◽  
Construction Contractor ◽  
Cold Bends ◽  
And Control ◽  
Design And Construction

Abstract Thermally insulated hot buried pipelines pose a unique set of challenges. This paper discusses those challenges and how they were met during design and construction of the 150 km long Husky LLB Direct Pipeline, the longest thermally insulated oil pipeline in Canada. Thermal insulation materials are soft and can be easily damaged during construction and backfilling, and by large restraining forces at bends when the pipeline is operating at high temperatures. The large temperature difference between pipeline installation temperature and maximum operating temperature leads to large axial compressive forces that can cause movement at bends, crush insulation, increase temperatures at ground surface, cause loss of restraint, and in the worst case, lead to upheaval buckling and loss of containment. Special design and construction features to deal with these challenges, including insulation specifications, insulation of pipe bends, pipeline pre-straining, long radius bends, deeper burial, and pipeline roping, were therefore necessary. After pipe has been insulated with polyurethane foam it cannot be bent in standard field bending machines used for uninsulated pipes because the foam is too soft. The induction bends and cold bends that are shop insulated after bending are expensive. The Project minimized the number of these expensive insulated bends by using an engineered ditch bottom profile. This meant that shop bends were only needed to reduce excavation depth at sharp changes in ground surface elevation where the roped profile required excessive grading. Care was therefore necessary in the selection and development of specifications for the insulation system and shop fabricated bends, and to design and construct a ditch profile to minimize forces on the insulation and control upheaval buckling. Close co-ordination with vendors and the construction contractor was crucial for a successful and timely completion.

Passive Cooling of Permafrost Foundation Soils Using Porous Embankment Structures

2000 ◽  
Author(s):  
Douglas J. Goering
Keyword(s):  
Land Surface ◽  
Thermal Characteristics ◽  
Ground Surface ◽  
Element Model ◽  
Passive Cooling ◽  
Frozen Ground ◽  
Foundation Soil ◽  
Dimensional Finite Element ◽  
Permafrost Thawing ◽  
Surface Construction

Abstract Permafrost (permanently frozen ground) underlies approximately 25% of the world’s land surface. Construction of surface facilities in these regions presents unique engineering challenges due to the alteration of the thermal regime at the ground surface. Even moderate disturbance of the pre-existing ground surface energy balance can induce permafrost thawing with consequent settlement and damage to buildings, roadways, or other man-made infrastructure. The present work examines the thermal characteristics of embankments constructed of unconventional, highly porous materials. Using these materials, a passive cooling effect can be achieved due to the unstable density stratification and resulting natural convection that occur during winter months. The convection enhances transport of heat out of the embankment, thus cooling the lower portions of the embankment and underlying foundation soil and preserving the permafrost layer. Numerical results obtained with an unsteady two-dimensional finite element model are compared to experimental measurements taken in full-scale field installations for the cases of open and closed (impermeable) side-slope boundary conditions.

Two-Dimensional Nonlinear Earthquake Response Analysis of a Bridge-Foundation-Ground System

2008 ◽  
Vol 24 (2) ◽  
pp. 343-386 ◽  
Author(s):  
Yuyi Zhang ◽  
Joel P. Conte ◽  
Zhaohui Yang ◽  
Ahmed Elgamal ◽  
Jacobo Bielak ◽  
...  
Keyword(s):  
Lateral Spreading ◽  
Soil Liquefaction ◽  
Earthquake Response ◽  
Response Analysis ◽  
Fe Model ◽  
Two Dimensional ◽  
Foundation Soil ◽  
Soil Medium ◽  
Surface Plasticity ◽  
Earthquake Response Analysis

This paper presents a two-dimensional advanced nonlinear FE model of an actual bridge, the Humboldt Bay Middle Channel (HBMC) Bridge, and its response to seismic input motions. This computational model is developed in the new structural analysis software framework OpenSees. The foundation soil is included to incorporate soil-foundation-structure interaction effects. Realistic nonlinear constitutive models for cyclic loading are used for the structural (concrete and reinforcing steel) and soil materials. The materials in the various soil layers are modeled using multi-yield-surface plasticity models incorporating liquefaction effects. Lysmer-type absorbing/transmitting boundaries are employed to avoid spurious wave reflections along the boundaries of the computational soil domain. Both procedures and results of earthquake response analysis are presented. The simulation results indicate that the earthquake response of the bridge is significantly affected by inelastic deformations of the supporting soil medium due to lateral spreading induced by soil liquefaction.

scholarly journals Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling

2013 ◽  
Vol 9 (1) ◽  
pp. 119-133 ◽  
Author(s):  
D. Mottaghy ◽  
G. Schwamborn ◽  
V. Rath
Keyword(s):  
Surface Temperature ◽  
Thermal Regime ◽  
Climate Changes ◽  
Ground Surface ◽  
Temperature Data ◽  
Ice Age ◽  
Drilling Process ◽  
Past Climate ◽  
Ground Surface Temperature ◽  
Recent Climate

Abstract. This study focuses on the temperature field observed in boreholes drilled as part of interdisciplinary scientific campaign targeting the El'gygytgyn Crater Lake in NE Russia. Temperature data are available from two sites: the lake borehole 5011-1 located near the center of the lake reaching 400 m depth, and the land borehole 5011-3 at the rim of the lake, with a depth of 140 m. Constraints on permafrost depth and past climate changes are derived from numerical simulation of the thermal regime associated with the lake-related talik structure. The thermal properties of the subsurface needed for these simulations are based on laboratory measurements of representative cores from the quaternary sediments and the underlying impact-affected rock, complemented by further information from geophysical logs and data from published literature. The temperature observations in the lake borehole 5011-1 are dominated by thermal perturbations related to the drilling process, and thus only give reliable values for the lowermost value in the borehole. Undisturbed temperature data recorded over more than two years are available in the 140 m deep land-based borehole 5011-3. The analysis of these observations allows determination of not only the recent mean annual ground surface temperature, but also the ground surface temperature history, though with large uncertainties. Although the depth of this borehole is by far too insufficient for a complete reconstruction of past temperatures back to the Last Glacial Maximum, it still affects the thermal regime, and thus permafrost depth. This effect is constrained by numerical modeling: assuming that the lake borehole observations are hardly influenced by the past changes in surface air temperature, an estimate of steady-state conditions is possible, leading to a meaningful value of 14 ± 5 K for the post-glacial warming. The strong curvature of the temperature data in shallower depths around 60 m can be explained by a comparatively large amplitude of the Little Ice Age (up to 4 K), with low temperatures prevailing far into the 20th century. Other mechanisms, like varying porosity, may also have an influence on the temperature profile, however, our modeling studies imply a major contribution from recent climate changes.

Sign in / Sign up

Export Citation Format

Share Document