Canadian Dam Association Bulletin - Summer 2016 - 19

CREST OF DAM RIGHT ABUTMENT SILTY SAND TO GRAVELLY SAND D-2 D-85 STRATIFIED SAND AND GRAVEL/ SILTY SANDS GRAVELLY SAND D-84 D-44 D-1 D-5 HORIZONTAL: VERTICAL: 0 0 20 10 10 20 ORGINAL GROUND SURFACE FD-87-2 STRATIFIED SILTY SAND SCALE (m) LEFT ABUTMENT D-64 D-6 FD-85-9 STRATIFIED SILTY SAND WITH GRAVEL/ GRAVEL WITH SAND AND SILT GRAVELLY SAND WITH COBBLES STRATIFIED SAND WITH GRAVEL COBBLES AND BOULDERS STRATIFIED SILTY SAND/ SAND/ SILT TOP OF BEDROCK Figure 1: Cross-section along the alignment of the dam (adapted from GEI Consultants 1993). the alignment of the dam are composed of stratified deposits of silty sand and sandy silt with some zones containing gravel, cobbles or traces of clay. These deposits are as much as 44 m thick near the left abutment (Borehole D-6) and as little as 2 m thick near the right abutment (Borehole D-44). The soils were reported to be loose to compact. The groundwater level was encountered near the surface in the lower area of the valley (USACE 1938). Subsurface conditions are shown in Figure 1. 3.3 Primary Design Considerations Four primary design considerations were identified by the design team. Due to the fact that the dam would be constructed on a pervious foundation: 1. Characterization of the hydraulic conductivity of the foundation soils and seepage control. 2. Internal erosion in the foundation and in the dam. 3. Compaction of the locally available soils (silty sand) for construction of the embankment. Additionally, due to the foundation soils being identified as loose to compact and the presence of seams of silt: 4. Flow failure (static liquefaction) in the foundation due to the loading imposed by the dam. These considerat ions were addressed through special studies that included additional subsurface investigating, laboratory testing, test fills and field testing. Canadian Dam Association * Summer 2016 3.4 Design Alternative and Seepage Study Due to the relatively high permeability of the alluvial foundation, three design alternatives were considered to limit the flow and control seepage; a zoned earthfill embankment with a core of compacted clayey till and: 1. A blanket of low permeability soil extending from the core to the upstream cofferdam. 2. A sheet-pile cut-off wall extending from the bottom of the core to about mid-depth of the foundation soils. 3. Just the core for seepage control (USACE 1938; Brown 1940). Recognizing that the permeability testing of the reconstituted specimens of the initial investigation was future not representative of field conditions, specifically due to the stratified nature of the soils, a special study on the permeability of the foundation soils was conducted. This study was comprised of 6 boreholes and samples were obtained by pushing 50-mm-diameter, thin-walled steel tubes downwards into the soil as the boreholes were advanced. Falling-head and constant-head permeability test devices were constructed. Specimens of finegrained and fairly uniform sands were extracted from the tubes without destroying the stratification and their vertical and horizontal hydraulic conductivities (Kv and K h, respectively) were measured. The stratification of medium and brought to you by your Manitoba Hydro hydro.mb.ca 819767_Manitoba.indd 1 25/06/16 19 12:32 AM http://www.hydro.mb.ca http://www.lakeside-equipment.com http://hydro.mb.ca

Table of Contents for the Digital Edition of Canadian Dam Association Bulletin - Summer 2016

BOARD OF DIRECTORS
NEW WEBSITE LEADS CDA RECENT NON-TECHNICAL INNOVATIONS
ICOLD NEWS
THE FRANKLIN FALLS DAM: DESIGN, CONSTRUCTION AND RESPONSE TO THE 1982 GAZA (NEW HAMPSHIRE) EARTHQUAKE
CDA CONFERENCE 2016
CDA OFFERS ASSISTANCE AFTER BRAZIL DAM DISASTER
DAM SAFETY REVIEWS TECHNICAL BULLETIN
TIME TO RENEW YOUR MEMBERSHIP
NOTICE OF AGM
BUYERS’ GUIDE AND TRADE LIST
CALL FOR PAPERS
Canadian Dam Association Bulletin - Summer 2016 - cover1
Canadian Dam Association Bulletin - Summer 2016 - cover2
Canadian Dam Association Bulletin - Summer 2016 - 3
Canadian Dam Association Bulletin - Summer 2016 - 4
Canadian Dam Association Bulletin - Summer 2016 - 5
Canadian Dam Association Bulletin - Summer 2016 - 6
Canadian Dam Association Bulletin - Summer 2016 - BOARD OF DIRECTORS
Canadian Dam Association Bulletin - Summer 2016 - 8
Canadian Dam Association Bulletin - Summer 2016 - NEW WEBSITE LEADS CDA RECENT NON-TECHNICAL INNOVATIONS
Canadian Dam Association Bulletin - Summer 2016 - 10
Canadian Dam Association Bulletin - Summer 2016 - 11
Canadian Dam Association Bulletin - Summer 2016 - ICOLD NEWS
Canadian Dam Association Bulletin - Summer 2016 - 13
Canadian Dam Association Bulletin - Summer 2016 - THE FRANKLIN FALLS DAM: DESIGN, CONSTRUCTION AND RESPONSE TO THE 1982 GAZA (NEW HAMPSHIRE) EARTHQUAKE
Canadian Dam Association Bulletin - Summer 2016 - 15
Canadian Dam Association Bulletin - Summer 2016 - 16
Canadian Dam Association Bulletin - Summer 2016 - 17
Canadian Dam Association Bulletin - Summer 2016 - 18
Canadian Dam Association Bulletin - Summer 2016 - 19
Canadian Dam Association Bulletin - Summer 2016 - 20
Canadian Dam Association Bulletin - Summer 2016 - 21
Canadian Dam Association Bulletin - Summer 2016 - 22
Canadian Dam Association Bulletin - Summer 2016 - 23
Canadian Dam Association Bulletin - Summer 2016 - 24
Canadian Dam Association Bulletin - Summer 2016 - 25
Canadian Dam Association Bulletin - Summer 2016 - 26
Canadian Dam Association Bulletin - Summer 2016 - 27
Canadian Dam Association Bulletin - Summer 2016 - 28
Canadian Dam Association Bulletin - Summer 2016 - 29
Canadian Dam Association Bulletin - Summer 2016 - 30
Canadian Dam Association Bulletin - Summer 2016 - 31
Canadian Dam Association Bulletin - Summer 2016 - 32
Canadian Dam Association Bulletin - Summer 2016 - 33
Canadian Dam Association Bulletin - Summer 2016 - CDA CONFERENCE 2016
Canadian Dam Association Bulletin - Summer 2016 - 35
Canadian Dam Association Bulletin - Summer 2016 - 36
Canadian Dam Association Bulletin - Summer 2016 - 37
Canadian Dam Association Bulletin - Summer 2016 - 38
Canadian Dam Association Bulletin - Summer 2016 - 39
Canadian Dam Association Bulletin - Summer 2016 - 40
Canadian Dam Association Bulletin - Summer 2016 - 41
Canadian Dam Association Bulletin - Summer 2016 - 42
Canadian Dam Association Bulletin - Summer 2016 - 43
Canadian Dam Association Bulletin - Summer 2016 - 44
Canadian Dam Association Bulletin - Summer 2016 - 45
Canadian Dam Association Bulletin - Summer 2016 - 46
Canadian Dam Association Bulletin - Summer 2016 - CDA OFFERS ASSISTANCE AFTER BRAZIL DAM DISASTER
Canadian Dam Association Bulletin - Summer 2016 - 48
Canadian Dam Association Bulletin - Summer 2016 - 49
Canadian Dam Association Bulletin - Summer 2016 - 50
Canadian Dam Association Bulletin - Summer 2016 - DAM SAFETY REVIEWS TECHNICAL BULLETIN
Canadian Dam Association Bulletin - Summer 2016 - 52
Canadian Dam Association Bulletin - Summer 2016 - NOTICE OF AGM
Canadian Dam Association Bulletin - Summer 2016 - BUYERS’ GUIDE AND TRADE LIST
Canadian Dam Association Bulletin - Summer 2016 - 55
Canadian Dam Association Bulletin - Summer 2016 - CALL FOR PAPERS
Canadian Dam Association Bulletin - Summer 2016 - 57
Canadian Dam Association Bulletin - Summer 2016 - 58
Canadian Dam Association Bulletin - Summer 2016 - cover3
Canadian Dam Association Bulletin - Summer 2016 - cover4
Canadian Dam Association Bulletin - Summer 2016 - outsert1
Canadian Dam Association Bulletin - Summer 2016 - outsert2
Canadian Dam Association Bulletin - Summer 2016 - outsert3
Canadian Dam Association Bulletin - Summer 2016 - outsert4
Canadian Dam Association Bulletin - Summer 2016 - outsert5
Canadian Dam Association Bulletin - Summer 2016 - outsert6
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