The Beaver Creek retrogressive landslide: a reevaluation
Date
1981-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Degree Level
Masters
Abstract
An analysis of the Beaver Creek retrogressive landslide
south of Saskatoon, Saskatchewan was undertaken. Supplemented
by data from previous studies of the landslide, information from the
installation of four inclinometers and three piezometers was sufficient
to describe the field behaviour of the retrogressive landslide and
to determine an appropriate procedure for analysis. Additional information
was provided by laboratory measurements such as direct
shear testing of field samples. The Morgenstern-Price method was
used for the stability analyses.
Slope indicator measurements made over a three year
period starting in August, 1977 clearly indicate the presence of
separate blocks within the landslide with the rate of movement increasing
from the scarp to the toe. Total movement at the toe is
estimated at 175 mm, while movement at the scarp has been 65 mm. The
rates of movement vary throughout the year with increases and decreases
in the movement rate corresponding to increases and decreases
in the piezometric level as measured by piezometers in the landslide
site as well as those indicated by an observation well near the site.
A common failure plane is located well below the river
elevation at the contact between the stratified lacustrine deposits
and the underlying tills. The landslide continues to retrogress, as
is indicated by the formation of a new block at the scarp. This
retrogression appears to be in response to erosion at the toe of the landslide.
Stability analyses have shown that for the Beaver Creek
landslide, the blocks within the sliding mass can be considered as a
singular unit for purposes of computing the factor of safety. However,
a series of blocks starting from the toe can also be analyzed in a conventional
manner. The shear strength mobilized by the Beaver Creek
landslide is approximately 7.0 degrees, plus or minus 1.0 degree, which
agrees favourably with the 6.6 to 10.6 degree range of residual shear
strength measured in the laboratory.
Note:Page 163 appears in the document twice, but page 164 is not included. The second page 163 should be labelled page 164.
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Citation
Degree
Master of Science (M.Sc.)
Department
Civil Engineering
Program
Civil Engineering