the baw codes of practice to ensure the bank stability of german inland waterways
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Bernhard Odenwald
The BAW codes of practice to ensure the bank stability of German inland waterways
Workshop on Seepage Induced Geotechnical Instability
Imperial College London, UK 31st Aug – 1st Sept 2017
www.baw.de |
Content
2017-30-08
1. German Federal Waterways – Hydraulic Structures 2. Cases of Damage at German Waterways 3. Conclusions and Consequences of the Assessment of the Damages 4. BAW Code of Practice Stability of Embankments at German Inland Waterways
(MSD) 5. BAW Code of Practice Use of Granular Filters on German Inland Waterways
(MAK) 6. BAW Code of Practice Internal Erosion (MMB)
Page 2 BAW codes of practice - bank stability of waterways | Bernhard Odenwald
www.baw.de | 2017-30-08
German Federal Waterways
Inland Waterways total length: 7.310 km canals: 1.740 km rivers: • barrage controlled: 3.030 km • free flowing: 2.540 km
Waterway Structures: • locks: 335 • weirs: 287 • canal bridges: 15
Embankments total distance: about 600 km
Page 3 BAW codes of practice - bank stability of waterways | Bernhard Odenwald
www.baw.de | 2017-30-08
Canal Embankments and Hydraulic Structures
Elbe Lateral Canal
Page 4 BAW codes of practice - bank stability of waterways | Bernhard Odenwald
Source: WSA Uelzen
Source: Wikipedia, Axel Hindemith
Source: WSA Uelzen
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald 2017-30-08 page 5
Embankments at Barrage Controlled Rivers
Iffezheim Barrage Upper River Rhine
Source: WSA Freiburg
Source: WSA Freiburg
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald 2017-30-08 page 6
Case of Damage at Elbe Lateral Canal (1976)
dam breach at road tunnel after flooding of a new canal section
Source: Wikipedia, Joachim Müllerchen Source: WSV, investigation of damages
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald 2017-30-08 page 7
Case of Damage at Main-Danube-Canal (1979)
dam breach at crossing with underlying water transport pipe after flooding of a new canal section
Source: BAW Source: BAW
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald 2017-30-08 page 8
Case of Damage at Main-Danube-Canal (1979)
flooding of the village of Katzwang, heavy damages
Source: BAW Source: WSA Nürnberg
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald 2017-30-08 page 9
Conclusions - Impacts on Embankment Stability
• embankments at waterways permanently loaded by water
• embankment stability reduced by seepage forces
failure of the impervious lining of the canal bed with resulting seepage through embankments must be taken into account (accidental design situation)
• increased damage potential at junctions with structures in embankments • different stiffness of soil embankment and concrete structure • possible development of erosion channels along structures (piping) cause by
seepage flow
verification against piping for embankments with structures inside considering possible hydraulically effective joints (cavities) along structure/soil interface
prevention of soil material losses by appropriate measures taking into account filter criteria and internal erosion processes
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald 2017-30-08 page 10
Consequence of the assessment of the damages BAW Code of Practice Stability of Embankments at German Inland Waterways (MSD)
directly downloadable www.baw.de > service and knowledge > publications > rules and standards > MSD (2011)
• provides rules for assessing the stability of embankments, taking account of seepage through embankments
• covers the influence of structures in embankments (separate piping verification procedure taking account of possible cavities along structure/soil interfaces)
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 11
BAW Code of Practice Stability of Embankments at German Inland Waterways (MSD)
Verification against Piping at Structures in Embankments
sufficient safety against piping
no risk of soil loss if water seeps through the embankment
(e. g. because of a local damage in the impervious lining of a canal)
sufficient safety against uplift
or hydraulic heave
sufficient safety against
slope failure + sufficient safety against
internal erosion in the percolated zones +
hydraulically effective joints (cavities) along a structure/soil interface are assumed, wherever the formation of cavities cannot be ruled out due to the particular
features of the ground, the geometry of the structure or the construction method
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald 2017-30-08 page 12
BAW Code of Practice Use of Granular Filters on German Inland Waterways (MAK)
directly downloadable www.baw.de > service and knowledge > publications > rules and standards > MAK (2013)
covers practical advices for design and construction of granular filters used in • embankments, • bank and bottom protection and • other structures on waterways
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 13
BAW Code of Practice Use of Granular Filters on German Inland Waterways (MAK)
Standard two-stage filter for revetments at inland waterways
Acceptable ranges for grading curves in a standard two-stage filter
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 14
BAW Code of Practice Internal Erosion (MMB)
directly downloadable www.baw.de > service and knowledge > publications > rules and standards > MMB (2011)
• describes verification methods based on geometric criteria of the soil structure
• recommended for dealing with specific hydraulic issues, e.g. • design of granular filters according to MAK (2013) or • verification of internal stability according to MSD (2011)
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 15
BAW Code of Practice Internal Erosion (MMB)
• Erosion
• migration and transport of almost all grain size fractions of a soil caused by the flow of water
• contact erosion • at the interface between two soils of different composition
• piping • at the interface between solid structures and the soil or • between a cohesive soil and an underlying cohesionless soil
layer
Types of internal erosion
• Suffosion
• migration and transport of the fine soil fractions through the pores of the granular skeleton of the coarse fractions
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 16
recommended procedure for verification of safety
against suffusion
BAW Code of Practice Internal Erosion (MMB)
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 17
BAW Code of Practice Internal Erosion (MMB)
Examples of verifications of safety against suffusion (according to Kenney and Lau)
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 18
BAW Code of Practice Internal Erosion (MMB)
verification of safety against contact erosion method following Lafleur’s approach
suffosive soils
non-suffosive soils
www.baw.de |
BAW codes of practice - stability of embankments | Bernhard Odenwald 21.03.2017 page 19
BAW Code of Practice Internal Erosion (MMB)
verification of safety against contact erosion for cohesive soils
Soil types and verification criteria according to Sherard
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald
Comparative assessment of the verification procedures
2017-30-08 Page 20
www.baw.de |
BAW codes of practice - bank stability of waterways | Bernhard Odenwald
Results of the comparison calculations
2017-30-08 Page 21
non-suffosive soil
suffosive soil
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