Distribution of saline permafrost in the Northwest Territories, Canada

1993 ◽  
Vol 30 (3) ◽  
pp. 506-514 ◽  
Author(s):  
E.G. Hivon ◽  
D.C. Sego

Saline permafrost has a detrimental impact on the performance of foundations. Increased pore-water salinity decreases the strength and increases the deformation susceptibility of permafrost and foundations installed in permafrost. A data base of the distribution of saline permafrost in the Northwest Territories shows high pore-water salinities beneath coastal communities and at locations along the upper Mackenzie Valley and within the Mackenzie Delta. Salinity of inland sites is usually low. High salinities are usually associated with ice-poor materials and are linked with previous marine submergence associated with glacial events. Key words : permafrost, saline distribution, measurements, Quaternary geology.

1986 ◽  
Vol 23 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Guy Lefebvre ◽  
Karol Rohan ◽  
Jean-Pierre Milette

Erodibility drill hole tests have been conducted on three Eastern Canadian clays on intact structured specimens, on specimens destructured by consolidation, and on remolded and reconsolidated specimens. The intact structured clay is highly resistant to erosion; links between particles can resist high tractive stresses. The resistance to erosion is drastically decreased however when the clay is destructured by consolidation or remolding. The decrease varies from one clay to the other; after consolidation the resistance to erosion is very low for the St. Hyacinthe clay but still high for the St. Leon clay. The clays are even more erodible after remolding and reconsolidation, but important differences are still observed between the clays tested. The pore water salinity appears as a significant factor in the understanding of the different behaviour observed after destructuration of the clay by consolidation or remolding. Key words: erosivity, rate of erosion, critical tractive stress, structured clay, destructuration, consolidation, remolding, pore water salinity.


1998 ◽  
Vol 64 (1) ◽  
pp. 359-362 ◽  
Author(s):  
Matthias Kästner ◽  
Maren Breuer-Jammali ◽  
Bernd Mahro

ABSTRACT Degradation of polycyclic aromatic hydrocarbons (PAHs) and survival of bacteria in soil was investigated by applying different inoculation protocols. The soil was inoculated with Sphingomonas paucimobilis BA 2 and strain BP 9, which are able to degrade anthracene and pyrene, respectively. CFU of soil bacteria and of the introduced bacteria were monitored in native and sterilized soil at different pHs. Introduction with mineral medium inhibited PAH degradation by the autochthonous microflora and by the strains tested. After introduction with water (without increase of the pore water salinity), no inhibition of the autochthonous microflora was observed and both strains exhibited PAH degradation.


2021 ◽  
pp. 106252
Author(s):  
Yongfeng Deng ◽  
Haochen Xue ◽  
Yongxin Wu ◽  
Tongwei Zhang ◽  
Zilong Wu ◽  
...  

1990 ◽  
Vol 27 (2) ◽  
pp. 203-215 ◽  
Author(s):  
J.-M. Konrad

Laboratory freezing tests were performed on a saturated clayey silt at various pore-water salinities and applied pressures to establish the relationships between pore-water salinity, overburden, and the amount of moisture transfer during freezing near thermal steady state conditions. The experimental data confirmed that the concept of segregation potential established for salt-free soils can be extended to saline soils. The segregation potential at the onset of the final ice lens in step-freezing tests (or near thermal steady state) should be related to the average salinity of the frozen fringe associated with the final ice lens. This pore-water salinity is different from the initial pore-water salinity as a result of solute exclusion at the ice lenses causing an enrichment as freezing proceeds. Unfortunately, it is very difficult to determine the average salinity in the frozen fringe owing to its small size. Instead, it is proposed to use the initial water salinity to develop the constitutive equations in freezing saline soils. A procedure for frost heave predictions in the field is outlined. Key words: freezing tests, clayey silt, saline water, frost heave.


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