Construction de la paroi au coulis ciment-bentonite sous la digue nord de l'aménagement hydroélectrique La Grande 1

1999 ◽  
Vol 26 (2) ◽  
pp. 145-155 ◽  
Author(s):  
Michel Massiéra ◽  
Jerry Levay

As part of the La Grande complex, in northern Québec, the development of the LG-1 hydroelectric project required the construction of a 2444 m long dyke on the north shore. The presence of a wide sensitive marine clay terrace covered with deltaic and river sand and silt deposits called for several design features, including the construction of a cement-bentonite cutoff through the sand and silt deposits on the terrace. This paper describes the different construction phases of the cement-bentonite cutoff with emphasis on excavation procedure and quality control.Key words: bentonite, cement, construction, cutoff, excavation, slurry trench.

1995 ◽  
Vol 22 (4) ◽  
pp. 723-735 ◽  
Author(s):  
Michel Massiéra ◽  
Jerry Levay

LG-1 hydroelectric project, part of La Grande Complex in northern Quebec, required the construction of a 2444 m long dyke on the north bank. The presence of sensitive marine clay, with deltaic and river sand and silt deposits on top of the clay in the central terrace, called for special design features. These included the construction of a dyke with side berms in a depression to ensure stability and the construction of a cement–bentonite cutoff through the sand and silt deposits of the terrace. This paper describes the different phases of dyke construction with emphasis on foundation treatment and construction techniques. Key words: bentonite, cement, clay, construction, cutoff, dyke, excavation, foundation, slurry, trench.


2000 ◽  
Vol 37 (1) ◽  
pp. 40-55
Author(s):  
Michel Massiéra ◽  
Jean-Pierre Tournier

The La Grande 1 (LG-1) hydroelectrical project, part of the La Grande Complex in Northern Quebec, required the construction of a 2444 m long dyke on the north bank of the river. The presence of sensitive marine clay, covered with deltaic sand and silt deposit, and river sand deposit, called for special design features such as downstream bank and upstream bank stabilization berms to avoid the occurrence of potentially disastrous retrogressive slides. This paper describes the geotechnical and hydrogeological conditions of the northern terrace and presents the different construction phases of the riverbank stabilization, with emphasis on the control of groundwater pressures in the lower aquifer by the use of relief wells.Key words: sensitive clay, river bank, dyke, rockfill, relief well, slope stability.


2012 ◽  
Vol 46 ◽  
pp. 298-305 ◽  
Author(s):  
A. D. Potemkin ◽  
T. Ahti

Riccia marginata Lindb. was described by S. O. Lindberg (1877) from the outskirts of the town of Sortavala near the north shore of Lake Ladoga, Republic of Karelia, Russia. The species has been forgotten in most recent liverwort accounts of Europe, including Russia. Lectotypification of R. marginata is provided. R. marginata shares most characters with R. beyrichiana Hampe ex Lehm. It differs from “typical” plants of R. beyrichiana in having smaller spores, with ± distinctly finely areolate to roughly papillose proximal surfaces and a narrower and shorter thallus, as well as in scarcity or absence of marginal hairs. It may represent continental populations of the suboceanic-submediterranean R. beyrichiana, known in Russia from the Leningrad Region and Karelia only. The variability of spore surfaces in R. beyrichiana is discussed and illustrated by SEM images. A comparison with the spores of R. bifurca Hoffm. is provided. The question how distinct R. marginata is from R. beyrichiana needs to be clarified by molecular studies in the future, when adequate material is available. R. marginata is for the time being, provisionally, included in R. beyrichiana.


2021 ◽  
Vol 86 (2) ◽  
pp. 350-367
Author(s):  
Jennifer Birch ◽  
John P. Hart

We employ social network analysis of collar decoration on Iroquoian vessels to conduct a multiscalar analysis of signaling practices among ancestral Huron-Wendat communities on the north shore of Lake Ontario. Our analysis focuses on the microscale of the West Duffins Creek community relocation sequence as well as the mesoscale, incorporating several populations to the west. The data demonstrate that network ties were stronger among populations in adjacent drainages as opposed to within drainage-specific sequences, providing evidence for west-to-east population movement, especially as conflict between Wendat and Haudenosaunee populations escalated in the sixteenth century. These results suggest that although coalescence may have initially involved the incorporation of peoples from microscale (local) networks, populations originating among wider mesoscale (subregional) networks contributed to later coalescent communities. These findings challenge previous models of village relocation and settlement aggregation that oversimplified these processes.


1984 ◽  
Vol 74 (2) ◽  
pp. 595-603
Author(s):  
F. M. Anglin

Abstract Continuous monitoring of the seismically active Charlevoix zone since late 1977 has delineated the boundaries of the earthquake zone under the north shore and has enabled an association to be made with surface mapped faults that strike along the St. Lawrence Valley and dip to the southeast. Within the active zone, aseismic volumes are found under parts of the St. Lawrence River and another elongated zone of activity is found to the southeast on unmapped faults dipping under the river. The previous suggestions that the activity is related to old rift faults, which have been later weakened by a meteor impact, would seem to be upheld.


2015 ◽  
Vol 129 (1) ◽  
pp. 80 ◽  
Author(s):  
Jordan Catrysse ◽  
Emily Slavik ◽  
Jonathan Choquette ◽  
Ashley E. Leifso ◽  
Christina M. Davy

We report a mass mortality of Northern Map Turtles (Graptemys geographica [LeSueur, 1817]) on the north shore of Lake Erie, Ontario, Canada. Thirty-five dead adult females were recovered from a nesting area over a period of four weeks. Predation and boat strikes were both excluded as potential cause of death, but the actual cause could not be determined because of the poor condition of the carcasses. Other possible explanations for the mortality include poisoning, drowning, and infection with an unidentified pathogen. Mass mortality in long-lived species, such as turtles, can have long-term effects on population growth and is a cause for concern in a species at risk.


1950 ◽  
Vol 82 (12) ◽  
pp. 250-252 ◽  
Author(s):  
W. W. Judd

On July 12, 1950 a collection of adults of the moth Acentropus niveus (Oliv.) was made on the north shore of Lake Erie near the village of South Cayuga, Ontario (Maps A, B-3). At the southern limits of the townships of Dunn and South Cayuga (Haldimand County) a shallow bay extends for a distance of about two miles along the shore of the lake (Map A). Along this bay is a sandy or gravelly beach ten to twenty yards wide backed by a cliff of clay that rises abruptly above the beach. On the day the collections were made the sky was clear and a brisk southerly breeze was causing waves to wash on the beach. The action of the waves had deposited debris, consisting largely of tangled masses of a filamentous green alga and exuviae of the mayfly Hexagenia occulta, in a windrow six inches to two feet wide along the shore. The moths ere found in this debris, most of them lying dead and with bedraggled wings, while some lay on their backs with wings stuck to the damp surface and with legs kicking and a few were crawling about on the debris.


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