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TitleGeotechnical data from a large landslide site at Quyon, Quebec
AuthorWang, B; Brooks, G R; Hunter, J A M
SourceGeological Survey of Canada, Open File 7904, 2015, 54 pages,
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatpdf
AreaQuyon; Quyon River
Lat/Long WENS-76.5000 -76.0000 45.7500 45.5000
Subjectsengineering geology; geophysics; landslides; health hazards; slope failures; slope stability; slope stability analyses; slope deposits; overburden thickness; seismic velocities; velocity surveys; boreholes; geophysical logging; Quyon landslide; Champlain Sea; Champlain Sea deposits; geotechnical surveys
Illustrationstables; plots; schematic diagrams
Natural Resources Canada Library - Ottawa (Earth Sciences)
ProgramWestern Canada Geohazards Project, Public Safety Geoscience
Released2015 11 18
AbstractA geotechnical study was initiated in 2014 to investigate the triggering mechanism of an enormous prehistorical landslide near Quyon, Quebec. The study consisted of surveys of the thickness of the glaciolacustrine deposits with a hand held seismograph, cone penetrometer testing (CPT), seismic cone penetrometer testing (SCPT), field vane shear testing (VST), soil sampling, and laboratory testing. Preliminary results were presented in a separate paper. This Open File provides more detailed information and updated data. In summary, the measured thickness of the Champlain Sea deposits in the region ranges from 0 m (at bedrock outcrops) to 68 m. The underlying bedrock surface forms a buried valley underlying the modern Quyon River. The glaciomarine sediments consist of clay, silty clay or clayey silt. The materials from the southern area are finer than that of the northern area. The materials in the southern area exhibit a high to extremely high plasticity with Plasticity Index ranging from 38.6% to 68.6%. The materials from the northern area have low to high plasticity with the Plasticity Index ranging from 13.9% to 33.0%. The clay/silt samples from 30 m depth and above have moisture content higher than the liquid limit in both the northern and southern areas. The CPT bearing factor Nkt was calibrated to be 11.5. The pore pressure bearing factor N?u varies with pore water pressure parameter Bq. The soil undrained shear strength (Su) ranges from 22 kPa to 250 kPa. The Su profiles determined from Nkt and N?u are identical. A clay unit of continuous Su profile was identified at three CPT locations in the undisturbed areas outside the landslide scar. Absence of the low strength material and discontinuity of the Su profiles were observed at upper elevations in the drill holes inside the landslide scar, which suggest that the upper clay unit either flowed away or was dislocated.
Summary(Plain Language Summary, not published)
This Open File report summarizes geotechnical data obtained from the 2014-2015 investigations of a large pre-historical landslide at Quyon, Québec. Previous studies concluded that the landslide was triggered by a magnitude 6.1 earthquake about a thousand years ago. This information is important for eastern Canada's earthquake catalogue that is used for the National Building Code. However, the triggering earthquake was estimated using empirical correlations that are based on other compiled earthquake data. Geotechnical studies are necessary to confirm the earthquake triggering mechanism and magnitude. We started a geotechnical investigation in 2014 including sediment thickness surveys, geotechnical drilling and laboratory testing. The data obtained from the first year include a map of the soft clay thickness in the region, the strength properties of the clay, and other geotechnical parameters necessary for understanding the behaviour of the clay. This report documents the detailed data.