Friday, January 27, 2017

There's a history of the Peace River's clay and silt Slip, Sliding, Away

A rapid flow slide on the Peace River, north-eastern B.C., involving 7 million m3 of overconsolidated clay and silt.  The deposit is approximately 1 km long 
(Fletcher et al., 2001, in review).

Failure behaviour of landslides in clay and silt:                                                   Top

Two large landslides in overconsolidated glacio-lacustrine clay and silt deposits of British Columbia river valleys have been examined.  Both cases are quite similar in their main aspects.  However, their failure behaviour was very different.  One continues to exhibit intermittent, manly ductile deformations with limited mobility, which are typical of compound landslides in stiff clay.  The other suddenly developed into a catastrophic, extremely rapid flow slide of 6.4 Mm3, damming a large river in the course of a few minutes and projecting a wave onto the opposite bank.  A comparison of the two cases has been made and possible mechanisms for brittle flow slide formation have been proposed (Fletcher et al., in review).

Fletcher, L., Hungr, O., Watson, A. and Thomson, B., 1999.  Failure mechanism and behaviour of a large landslide in glacio-lacustrine silt and clay, Chilliwack River Valley, B.C.
Proceedings, Slope Stability and Landslides, Vancouver Geotechnical Society Symposium May, 1999, 55-62.
August 2001



If this profile looks familiar, its just upstream from Fort St. John -- Site C?

 Google Search Criteria: Attachie Slide

 .... Starting about rive kilometer 63, low-lying terraces on the north sied of the valley could potentially be affected by waves caused by landslides orginating from the slopes adajcent to the 1973 Attachie landslide.

Map 8 of 26 – Attachie Slide - Site C


The Proceedings of past Vancouver Geotechnical Society Symposiums can be found at the links below.

 History of

Railway and Vehicular Bridge Across Vancouver Harbour, B.C. (Canada). - A. D. Swan, 1928
First Narrows Water Tunnel: Engineering News Record January 1, 1933 and July 6, 1933, and a paper (author unknown)
The Lions' Gate Bridge - S. M.  Banks, 1942
Granville Bridge Test Hole Logs - City Engineer's Office, City of Vancouver, 1950
Report on Preliminary Investigation of Foundation Conditions of Proposed Port Mann Bridge - R. A. Spence, 1958
Preliminary Geologic Report on Glacial Till and Till-Like Sediments Beneath Piers S4 and S2 of the Port Mann Bridge - W. L. Brown, 1960
Design of the Main Foundations of the Port Mann Bridge - H. Q. Golder and G. C. Willeumeir, 1964
Peat Symposium - Vancouver Soils Group, February 27, 1967
The Function of Shotcrete in Support and Lining of the Vancouver R.R. (Thornton) Tunnel - E. E. Mason, 1968
Earthquake Design in the Fraser Delta - Task Force Report, June 1991 (for comparison the 2007 Report)
Breaking New Ground - Women in Geotechnical Engineering - Anna Lankford Burwash, Geotechnical News, 1997

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