Centrifuge modelling of gas pipelines undergoing freeze–thaw cycles

Canadian Geotechnical Journal ◽

10.1139/cgj-2020-0482 ◽

2021 ◽

Author(s):

Rajith Sudilan Dayarathne ◽

Bipul C. Hawlader ◽

Ryan Phillips

Keyword(s):

Vertical Displacement ◽

Operating Conditions ◽

Frost Heave ◽

Seasonal Temperature ◽

Test Results ◽

Gas Pipelines ◽

Freezing And Thawing ◽

Geotechnical Centrifuge ◽

Freeze Thaw ◽

Cyclic Temperature

Frost heave and thaw settlement are two critical factors that need to be considered in the design of chilled gas pipelines in cold regions. Due to the variation in seasonal temperature and operating conditions (e.g., pressure and temperature at the compressor stations), the pipeline temperature in some segments might vary from subzero to above-zero during winter and summer. This study examines the freezing and thawing for cyclic and constant temperatures at the pipeline and ground surfaces based on the response of fourteen model pipes tested in a geotechnical centrifuge. The cyclic (temperature) operation reduces the frost heave rate per year and causes net settlement in some cases. When the thaw bulb resulting from an above-zero operating temperature is less than the previously developed frost bulb, upward water flow occurs through the thawed soil, which could alter the pipeline–soil interaction behaviour. Five types of freeze-thaw-induced vertical displacement of the pipe have been identified from the centrifuge test results.

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Study on a Method Monitoring Oil and Gas Pipelines in Permafrost Regions

Volume 4: Pipelining in Northern and Offshore Environments; Strain-Based Design; Risk and Reliability; Standards and Regulations ◽

10.1115/ipc2012-90126 ◽

2012 ◽

Author(s):

Yunbin Ma ◽

Dongjie Tan ◽

Ning Song ◽

Pengchao Chen ◽

Tao Ma

Keyword(s):

Temperature Field ◽

Oil And Gas ◽

Frost Heave ◽

Fiber Grating ◽

Test Results ◽

Gas Pipelines ◽

Monitoring Method ◽

Oil And Gas Pipelines ◽

The Impact ◽

Permafrost Regions

Based on conditions of oil and gas pipelines in permafrost regions, this paper demonstrates a method for monitoring pipeline stress and displacement as well as permafrost temperature field. To measure pipeline displacement, Total Station measuring technique which calculates displacement by measuring the change of pipeline sign post was adopted; and to monitor pipeline stress and temperature field of permafrost, Fiber Grating Sensing technique was used. This method has been applied to Pipeline No. A for a year, according to the test results, during the year, displacements of different degrees have been occurred to the pipeline; this pipeline was not influenced by frost heave in winter but was influenced by thaw collapse in summer. Due to this monitoring method for oil and gas pipelines in permafrost regions, the condition of permafrost and the change of pipeline under the impact of permafrost were successfully monitored; therefore, this method is effective and feasible.

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Study of Frost Resistance on Air-Entrained Concrete in Sulfated Medium

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.302-303.125 ◽

2006 ◽

Vol 302-303 ◽

pp. 125-130 ◽

Cited By ~ 1

Author(s):

Ge Yong ◽

Yuan Jie ◽

Wen Cui Yang ◽

Bao Sheng Zhang

Keyword(s):

Fresh Water ◽

Frost Resistance ◽

Plain Concrete ◽

Sulfate Solution ◽

Test Results ◽

Freezing And Thawing ◽

Freeze Thaw ◽

Freezing And Thawing Cycles ◽

Air Entrained Concrete ◽

Sodium Solution

Frost resistance of plain concrete and air-entrained concrete subjected to freeze-thaw cycles in fresh water and 5 % and 7 % sodium sulfate solution are investigated in this paper. The test results show that the frost resistance of concrete is different in the different medium. The properties of concrete frozen in 5 % and 7 % sodium solution are different from that in fresh water, and entraining air into concrete properly can increase the frost resistance significantly whether in fresh water or in sulfate solution. Higher strength concrete could resist the degradation of freezing and thawing cycles in water, but some of them failed suddenly in midspan of specimens under the sulfate solution.

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Mitigation of Frost Heave of Chilled Gas Pipelines Using Temperature Cycling

Volume 1: Project Management; Design and Construction; Environmental Issues; GIS/Database Development; Innovative Projects and Emerging Issues; Operations and Maintenance; Pipelining in Northern Environments; Standards and Regulations ◽

10.1115/ipc2006-10169 ◽

2006 ◽

Cited By ~ 1

Author(s):

Vincent Morgan ◽

Bipul Hawlader ◽

Joe Zhou

Keyword(s):

Effective Means ◽

Large Diameter ◽

Vertical Displacement ◽

Temperature Cycling ◽

Frost Heave ◽

Pipeline System ◽

Gas Temperature ◽

Physical Test ◽

Geotechnical Centrifuge ◽

Discontinuous Permafrost

A number of recent studies have been undertaken by the pipeline industry to improve understanding and design capability of frost heave issues related to the operation of large diameter chilled gas transmission pipelines through areas of discontinuous permafrost. These studies have included the assessment of methods of reducing the effects of frost heave on pipeline integrity, in particular the onset of significant bending strain due to differential vertical displacement of the pipeline. This paper will present one component of a study to investigate and assess the use of temperature cycling of the product as a means of reducing long-term frost heave of a pipeline system. The use of chillers at compressor station locations is considered a feasible method of controlling the gas temperature in the pipeline. The studies were undertaken using a geotechnical centrifuge as a cost effective means of obtaining physical test data under realistic soil stress conditions. The potential benefits of cyclic temperature operation in reducing pipeline strain are discussed.

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Effect of freeze–thaw cycles on the freezing characteristics of a clayey silt at various overconsolidation ratios

Canadian Geotechnical Journal ◽

10.1139/t89-031 ◽

1989 ◽

Vol 26 (2) ◽

pp. 217-226 ◽

Cited By ~ 21

Author(s):

J.-M. Konrad

Keyword(s):

Void Ratio ◽

Frost Heave ◽

Freezing And Thawing ◽

Freeze Thaw ◽

Maximum Reduction ◽

Clayey Silt ◽

Wide Range ◽

Repeated Freezing ◽

Segregation Potential ◽

Overconsolidated Soils

Repeated freezing and thawing affect the structure of clayey silts over a wide range of consolidation ratios. While the overall void ratio of the thawed soil either decreased, as in lightly overconsolidated soils, or increased, as in heavily overconsolidated samples, freezing and thawing caused a reduction in segregation potential after each freeze–thaw event. All the changes occurred during the first three cycles. The maximum reduction in segregation potential was about 50% in all samples. The implications for frost heave predictions in the field are discussed. Key words: freeze–thaw, clayey silt, segregation potential, frost heave.

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Hysteresis loss of ultra-large off-the-road tire rubber compounds based on operating conditions at mine sites

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/09544070211015525 ◽

2021 ◽

pp. 095440702110155

Author(s):

Shaosen Ma ◽

Guangping Huang ◽

Khaled Obaia ◽

Soon Won Moon ◽

Wei Victor Liu

Keyword(s):

Large Strain ◽

Tensile Tests ◽

Operating Conditions ◽

Hysteresis Loss ◽

Strain Rates ◽

Test Results ◽

Tire Rubber ◽

The Road ◽

Rubber Compounds ◽

Mine Sites

The objective of this study is to investigate the hysteresis loss of ultra-large off-the-road (OTR) tire rubber compounds based on typical operating conditions at mine sites. Cyclic tensile tests were conducted on tread and sidewall compounds at six strain levels ranging from 10% to 100%, eight strain rates from 10% to 500% s−1 and 14 rubber temperatures from −30°C to 100°C. The test results showed that a large strain level (e.g. 100%) increased the hysteresis loss of tire rubber compounds considerably. Hysteresis loss of tire rubber compounds increased with a rise of strain rates, and the increasing rates became greater at large strain levels (e.g. 100%). Moreover, a rise of rubber temperatures caused a decrease in hysteresis loss; however, the decrease became less significant when the rubber temperatures were above 10°C. Compared with tread compounds, sidewall compounds showed greater hysteresis loss values and more rapid increases in hysteresis loss with the rising strain rate.

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Methodology for Selecting the Operating Conditions of a Vibration Generator Used in the Hot-Dip Galvanizing Process

Materials ◽

10.3390/ma14082042 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2042

Author(s):

Wojciech Kacalak ◽

Igor Maciejewski ◽

Dariusz Lipiński ◽

Błażej Bałasz

Keyword(s):

Simulation Model ◽

Asynchronous Motor ◽

Experimental Tests ◽

Suspension System ◽

Operating Conditions ◽

Test Results ◽

Forced Simulation

A simulation model and the results of experimental tests of a vibration generator in applications for the hot-dip galvanizing process are presented. The parameters of the work of the asynchronous motor forcing the system vibrations were determined, as well as the degree of unbalance enabling the vibrations of galvanized elements weighing up to 500 kg to be forced. Simulation and experimental tests of the designed and then constructed vibration generator were carried out at different intensities of the unbalanced rotating mass of the motor. Based on the obtained test results, the generator operating conditions were determined at which the highest values of the amplitude of vibrations transmitted through the suspension system to the galvanized elements were obtained.

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Strength and Microscopic Damage Mechanism of Yellow Sandstone with Holes under Freezing and Thawing

Advances in Civil Engineering ◽

10.1155/2020/5921901 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Huren Rong ◽

Jingyu Gu ◽

Miren Rong ◽

Hong Liu ◽

Jiayao Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Pore Size ◽

Power Function ◽

Damage Mechanism ◽

Uniaxial Compression Test ◽

Freezing And Thawing ◽

Freeze Thaw ◽

Thaw Cycle ◽

Freeze Thaw Cycle ◽

Microscopic Damage

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.

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Earth pressures exerted on an induced trench cast-in-place double-cell rectangular box culvert

Canadian Geotechnical Journal ◽

10.1139/t2012-093 ◽

2012 ◽

Vol 49 (11) ◽

pp. 1267-1284 ◽

Cited By ~ 22

Author(s):

Olajide Samuel Oshati ◽

Arun J. Valsangkar ◽

Allison B. Schriver

Keyword(s):

Earth Pressure ◽

Test Results ◽

Overburden Pressure ◽

Centrifuge Testing ◽

Geotechnical Centrifuge ◽

Drag Forces ◽

Field Instrumentation ◽

Earth Pressures ◽

Box Culvert ◽

Base Contact

Earth pressure data from the field instrumentation of a cast-in-place reinforced rectangular box culvert are presented in this paper. The instrumented culvert is a 2.60 m by 3.60 m double-cell reinforced cast-in-place rectangular box buried under 25.10 m of fill constructed using the induced trench installation (ITI) method. The average earth pressure measured across the roof was 0.42 times the overburden pressure, and an average of 0.52 times the overburden pressure was measured at mid-height of the culvert on the sidewalls. Base contact pressure under the rectangular box culvert was also measured, providing field-based data demonstrating increased base pressure resulting from downward drag forces developed along the sidewalls of the box culvert. An average increase of 25% from the measured vertical earth pressures on the roof plus the culvert dead load (DL) pressure was calculated at the culvert base. A model culvert was also tested in a geotechnical centrifuge to obtain data on earth pressures at the top, sides, and base of the culvert. The data from the centrifuge testing were compared with the prototype structure, and the centrifuge test results agreed closely with the measured field prototype pressures, in spite of the fact that full similitude was not attempted in centrifuge testing.

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Review of Strength and Failure Criteria for Concrete After Freeze-Thaw Damage

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.253-255.456 ◽

2012 ◽

Vol 253-255 ◽

pp. 456-461

Author(s):

Yan Fu Qin ◽

Bin Tian ◽

Gang Xu ◽

Xiao Chun Lu

Keyword(s):

Normal State ◽

Concrete Strength ◽

Failure Criteria ◽

Concrete Durability ◽

Freezing And Thawing ◽

Normal Concrete ◽

Strength Criteria ◽

Freeze Thaw ◽

Ordinary Concrete ◽

Concrete Failure

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage，this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.

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