Mechanics of Buried Chilled Gas Pipelines

Author(s):  
A. P. S. Selvadurai ◽  
J. Hu

This paper examines the factors influencing the modelling of soil-pipeline interaction for a pipeline which is used to transport chilled gas. The soil-pipeline interaction is induced by the generation of discontinuous frost heave at a boundary between soils with differing frost susceptibility. The three-dimensional modelling takes into consideration the time-dependent evolution of frost heave due to moisture migration, the creep and elastic behaviour of the frozen soil and flexural behaviour of the embedded pipeline. The results of the computational model are compared with experimental results obtained from the frost heave induced soil-pipeline interaction test performed at the full scale test facilities in Caen, France.

Author(s):  
Jean Lafleur ◽  
Y. Savard

During winter the formation of ice lenses causes frost heave within frost-susceptible materials. The uneven spatial distribution of heave due to heterogeneity results in severe damage to the pavement. Fissures are created, favoring excess infiltration, especially during subsequent springtime thaw. The installation of drainage can be beneficial in reducing the amount of water present in road foundations. Some uncertainty, however, exists about the sources of water feeding the lenses and, therefore, the optimal location of the systems. To assess the efficiencies of deep lateral drainage systems, a full-scale test has been undertaken along an existing road constructed on a glacial till subgrade. Three 150-m-long vertical geocomposite systems were installed at depths ranging between 2 and 3 m. In situ monitoring included piezometers and frost indicators and measurements of flow rates and pavement heave. To obtain a point of comparison, the measurements started 1 year before drain installation. For the period of observation the freezing indexes ranged between 1432°C-day and 1558°C-day, and the maximum frost penetration was 2.5 m. The flow rates varied considerably with the seasons, ranging between 1 ml/sec/linear meter during winter and 10 ml/sec/m during the April thaw. Before drainage the heave values ranged between 50 and 150 mm. After installation they were reduced by a factor ranging between 10 and 50 percent.


1985 ◽  
Vol 22 (2) ◽  
pp. 283-290 ◽  
Author(s):  
M. W. Smith

Field observations of soil temperature, moisture regime, and frost heave in silty clay hummocks at Inuvik, Northwest Territories, over the fall and early winter reveal that a significant amount of moisture migration and frost heave occurs within frozen soil at temperatures down to −2.4°C. The field data are analysed using thermodynamic considerations, and the apparent hydraulic conductivity is determined as a function of negative temperature. The conductivity falls from near 7 × 10−9 m s−1 above 0 °C to about 3.5 × 10−12 m s−1 at −1 °C, then remains fairly constant down to −2.4 °C. The observed decrease in heave with time is explained in terms of a diminishing water supply at the base of the active layer.


ISCORD 2013 ◽  
2013 ◽  
Author(s):  
Shunji Kanie ◽  
Hao Zheng ◽  
Shohei Takahashi ◽  
Satoshi Akagawa ◽  
Yasushi Ueda

2012 ◽  
Vol 212-213 ◽  
pp. 260-263
Author(s):  
Ying Hao Wang ◽  
Shuo Li

Hetao irrigation area in Inner Mongolia is one of the four major irrigation areas in China, seasonal frozen soil is widely distributed in this area. Irrigation channel engineering experiences seriously freeze-thaw cycle many times in the long winter, its maintenance is the important and difficult point all long in irrigation channel engineering of Hetao irrigation area. For this, we analyze the moisture migration and law of frost heave characteristics of seasonal frozen soil in Hetao irrigation area.


1994 ◽  
Vol 1 (1) ◽  
pp. 77-83
Author(s):  
Yoshiji Moro ◽  
Tomoo Fujita ◽  
Takeshi Kanno ◽  
Akira Kobayashi

2019 ◽  
Vol 18 (1) ◽  
pp. 76-80 ◽  
Author(s):  
Kichul Kim ◽  
Pil-Ju Park ◽  
Soomi Eo ◽  
Seungmi Kwon ◽  
Kwangrae Kim ◽  
...  

1992 ◽  
Vol 35 (3) ◽  
pp. 977-985 ◽  
Author(s):  
K. G. Gebremedhin ◽  
J. A. Bartsch ◽  
M. C. Jorgensen

2020 ◽  
pp. 1420326X2097902
Author(s):  
Hai-Xia Xu ◽  
Yu-Tong Mu ◽  
Yin-Ping Zhang ◽  
Wen-Quan Tao

Most existing models and standards for volatile organic compounds emission assume that contaminants are uniform in the testing devices. In this study, a three-dimensional transient numerical model was proposed to simulate the mass transport process based on a full-scale test chamber with a mixing fan, and the airflow field and contaminants concentration distribution were obtained within the chamber under airtight and ventilated conditions. The model was validated by comparing the numerical results with experimental data. The numerical results show that the contaminant source position and the airflow field characteristics have significant impact on the contaminant mixing, and the fan rotation has an important role in accelerating mixing. In the initial mixing stage, the concentration distribution is obviously uneven; as the mixing progresses, it gradually reaches acceptable uniformity except for some sensitive regions, such as high concentration region at the injection point of the contaminants and low concentration region at the air inlet. To ensure test accuracy, the monitor should avoid above sensitive regions; and some special regions are recommended where contaminant concentration uniformity can be reached sooner. The ventilated chamber results indicate that the mixture of contaminants in the chamber is actually better than the results shown by conventional test method.


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