Site Investigation and Slope Stability Analysis of the Chitina Dump Slide (CDS), Alaska

Abstract

Research Article| February 01, 2013 Site Investigation and Slope Stability Analysis of the Chitina Dump Slide (CDS), Alaska KYLE E OBERMILLER; KYLE E OBERMILLER 1 University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 1Corresponding author email: kobermiller@golder.com Search for other works by this author on: GSW Google Scholar MARGARET M DARROW; MARGARET M DARROW University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 Search for other works by this author on: GSW Google Scholar SCOTT L HUANG; SCOTT L HUANG University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 Search for other works by this author on: GSW Google Scholar GANG CHEN GANG CHEN University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 Search for other works by this author on: GSW Google Scholar Author and Article Information KYLE E OBERMILLER 1 University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 MARGARET M DARROW University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 SCOTT L HUANG University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 GANG CHEN University of Alaska Fairbanks, P.O. Box 755800, Fairbanks, AK 99775-5800 1Corresponding author email: kobermiller@golder.com Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 © 2013 Association of Environmental & Engineering Geologists Environmental & Engineering Geoscience (2013) 19 (1): 27–40. https://doi.org/10.2113/gseegeosci.19.1.27 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation KYLE E OBERMILLER, MARGARET M DARROW, SCOTT L HUANG, GANG CHEN; Site Investigation and Slope Stability Analysis of the Chitina Dump Slide (CDS), Alaska. Environmental & Engineering Geoscience 2013;; 19 (1): 27–40. doi: https://doi.org/10.2113/gseegeosci.19.1.27 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract We present the mapping and subsurface analysis of a slide occurring in discontinuous permafrost located near Chitina, AK. Our investigation included mapping landslide features, conducting seismic surveys, collecting tree-ring samples for dendrogeomorphic analysis, and conducting a slope stability analysis to back-calculate residual soil strength properties. Referred to as the “Chitina Dump Slide” because of its previous use as a dump, the active slide intersects a state road and is an ongoing maintenance issue. The soils in the area consist of surficial silt overlying clayey glaciolacustrine diamicton, overlying bedrock. Drilling data indicated the deepening of the permafrost table in the active slide area from 6.1 m in 2005 to greater than 16.5 m in 2010. Field mapping indicated that the landslide extent is much larger than the active portion of the slide. The dendrogeomorphic analysis indicated that movement occurred in at least two portions of the area in the 1940s and in a third area later in the 1990s. Seismic surveys, with typical velocities ranging from 100 to 900 m/s, produced good correlation with drilling data and proved to be an effective method of subsurface imaging. From these observations, we conclude that the failure mechanism for the active portion of the slide is different than that of the overall slide area. Back-calculation of slope failure within the clay layer indicates a residual effective friction angle of 22°. Permafrost degradation due to the thermal effects of the dump may be a contributing factor in the ongoing movement of the active slide area. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.