|Title||Geotechnical data from a Champlain Sea clay landslide site in Breckenridge, southwestern Québec|
|Source||Canadian Geotechnical Journal .|
|Alt Series||Earth Sciences Sector, Contribution Series 20170046|
|Meeting||Geo Ottawa 2017; Ottawa; CA; October 1-4, 2017|
|Lat/Long WENS|| -76.0000 -75.5000 45.7500 45.5000|
|Subjects||surficial geology/geomorphology; geophysics; landslides; slope failures; clays; LEDA; marine clays; sensitive clays; slumps; Breckenridge; cone penetration tests; retrogressive failure|
|Illustrations||location maps; graphs; tables|
|Program||Assessing Earthquake Geohazards, Public Safety Geoscience|
|Abstract||This paper presents geotechnical test results from an ancient Champlain Sea clay landslide site at Breckenridge, southwestern Quebec. Cone penetration tests (CPT) and vane shear tests were conducted.
The CPT cone bearing factor Nkt was calibrated to be 11.5. The soil undrained shear strength (Cu) was found to have a correlation of Cu = 15 + 2.66 H (kPa), where H is depth in meters from the pre-failure ground surface at the head scarp. The slip
surface was found to be at about 15 m depth from the pre-failure ground surface. The soil properties suggest that the landslide unlikely occurred as a retrogressive failure commonly observed in sensitive clays (more likely an overall slope
|Summary||(Plain Language Summary, not published)|
A cluster of prehistoric clay landslides occurred in Breckenridge, Quebec. One of them was dated in a previous study to be about a thousand years old.
Evidence from this and other same aged landslides in the region indicated that an earthquake occurred and triggered the landslides. A geotechnical study was initiated to investigate those landslides for understanding the earthquake. The Breckenridge
landslide was one of three sites selected from the region for the geotechnical study. Field tests were conducted to determine the strength of the clay materials by pushing instruments into the ground and measuring the soil resistance. Soil samples
were collected for laboratory testing of other geotechnical properties. This paper presents the factual data obtained from the test programs. The data are useful for study of this and other landslides in the region.