Notes of presentation to YGG 11.04.2017
12/04/2017
1
Institution of Civil EngineersJohn Mitchell Lecture Registered charity number 210252. Charity registered in Scotland number SC038629.
2016 John Mitchell Lecture
– presented to YGG 11.04.17
Presented by Dr Martin Pedley
Joh
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itch
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Inst
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En
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Institution of Civil EngineersJohn Mitchell Lecture
Personal journey
Establishment of soil nailing in UK
Deep foundations – progressive development
Risk and cycle of re-learning
Developments in foundation engineering – a personal perspective
Notes of presentation to YGG 11.04.2017
12/04/2017
2
Institution of Civil EngineersJohn Mitchell Lecture
Developments in foundation engineering – a personal perspective
Foundation &business Risk management
Design Engineer
Joint Venture Manager
Technical management
Foundation design & research
Sitesupervision
Researchstudent
Industrial trainee1985
2015
Institution of Civil EngineersJohn Mitchell Lecture
Historical perspective
Fundamental research and validation of interactions
Challenge of developing standards
Soil nailing – establishment in the UK
Notes of presentation to YGG 11.04.2017
12/04/2017
3
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – example
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – example
Notes of presentation to YGG 11.04.2017
12/04/2017
4
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – example
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – example
Notes of presentation to YGG 11.04.2017
12/04/2017
5
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – example
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – historical perspective
Notes of presentation to YGG 11.04.2017
12/04/2017
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Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – soil reinforcement interaction
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – soil reinforcement interaction
Notes of presentation to YGG 11.04.2017
12/04/2017
7
Institution of Civil EngineersJohn Mitchell Lecture
Axial component Shear component
Soil nailing – soil reinforcement interaction
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – soil reinforcement interaction
Notes of presentation to YGG 11.04.2017
12/04/2017
8
Institution of Civil EngineersJohn Mitchell Lecture
S
X
Seffect of nail
Soil nailing – soil reinforcement interaction
S + S
X
Y
V AS
axS
Pax
PS
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – soil reinforcement interaction
V AS
Z
ELEVATION
L
V AS
500mm 500mm
PLAN
250mm
250mm
500mm
Reinforcement
Notes of presentation to YGG 11.04.2017
12/04/2017
9
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – soil reinforcement interaction
Jewell &Pedley (1990a)
Brinch Hansen& Lundgren (1960)
‐1 1 ‐0.03 0.03 0.06
LateralStress (/b)
ShearForce (PS/PP)
s2
s2
‐1
0.5
11
b
(z/L) (z/L)(z/L)
1
BendingMoment (M/MP)
Institution of Civil EngineersJohn Mitchell Lecture
Soil nailing – model validation through full scale test data (after Gassler)
Notes of presentation to YGG 11.04.2017
12/04/2017
10
Institution of Civil EngineersJohn Mitchell Lecture
V
H
L
R , f(V , H, L)
Soil nailing – soil reinforcement interaction
Institution of Civil EngineersJohn Mitchell Lecture
Soil nail standards – maturing of the technique?
Notes of presentation to YGG 11.04.2017
12/04/2017
11
Institution of Civil EngineersJohn Mitchell Lecture
Differences in foundation construction
Capabilities – larger and deeper
Analysis – Buildability – Standards balance
Deep foundations – progressive development
Institution of Civil EngineersJohn Mitchell Lecture
Deep foundations – progressive development
DeeperNew geologies
Structural complexity and scale
Notes of presentation to YGG 11.04.2017
12/04/2017
12
Institution of Civil EngineersJohn Mitchell Lecture
Deep foundation - construction safety
Institution of Civil EngineersJohn Mitchell Lecture
1985 2015
Retaining walls
Bearing piles
Design analysisand codes
Materials
Testing
25 – 35m deep1.0 – 1.2m thick
30 – 40m deep900 – 1,500mm
Spring stiffnessBritish StandardsFPS
Rebar 25 – 40mmConcrete 30 – 40N/mm²Bentonite
Reaction pilesSonic coring
30 – 50m deep1.2 – 1.5m thick
40 – 60m deep900 – 2,500mm
Finite elementEN’sICE SPERW
Rebar 32 – 50mmConcrete 45 – 50N/mm²Bentonite/Polymers
Bidirectional jacksThermal profiling
Deep foundations – progressive development
Notes of presentation to YGG 11.04.2017
12/04/2017
13
Institution of Civil EngineersJohn Mitchell Lecture
Institution of Civil EngineersJohn Mitchell Lecture
Notes of presentation to YGG 11.04.2017
12/04/2017
14
Institution of Civil EngineersJohn Mitchell Lecture
1985 2015
Retaining walls
Bearing piles
Design analysisand codes
Materials
Testing
25 – 35m deep1.0 – 1.2m thick
30 – 40m deep900 – 1,500mm
Spring stiffnessBritish StandardsFPS
Rebar 25 – 40mmConcrete 30 – 40N/mm²Bentonite
Reaction pilesSonic coring
30 – 50m deep1.2 – 1.5m thick
40 – 60m deep900 – 2,500mm
Finite elementEN’sICE SPERW
Rebar 32 – 50mmConcrete 45 – 50N/mm²Bentonite/Polymers
Bidirectional jacksThermal profiling
Deep foundations – progressive development
Institution of Civil EngineersJohn Mitchell Lecture
Notes of presentation to YGG 11.04.2017
12/04/2017
15
Institution of Civil EngineersJohn Mitchell Lecture
Institution of Civil EngineersJohn Mitchell Lecture
1985 2015
Retaining walls
Bearing piles
Design analysisand codes
Materials
Testing
25 – 35m deep1.0 – 1.2m thick
30 – 40m deep900 – 1,500mm
Spring stiffnessBritish StandardsFPS
Rebar 25 – 40mmConcrete 30 – 40N/mm²Bentonite
Reaction pilesSonic coring
30 – 50m deep1.2 – 1.5m thick
40 – 60m deep900 – 2,500mm
Finite elementEN’sICE SPERW
Rebar 32 – 50mmConcrete 45 – 50N/mm²Bentonite/Polymers
Bidirectional jacksThermal profiling
Deep foundations – development progression
Notes of presentation to YGG 11.04.2017
12/04/2017
16
Institution of Civil EngineersJohn Mitchell Lecture
Institution of Civil EngineersJohn Mitchell Lecture
1985 2015
Retaining walls
Bearing piles
Design analysisand codes
Materials
Testing
25 – 35m deep1.0 – 1.2m thick
30 – 40m deep900 – 1,500mm
Spring stiffnessBritish StandardsFPS
Rebar 25 – 40mmConcrete 30 – 40N/mm²Bentonite
Reaction pilesSonic coring
30 – 50m deep1.2 – 1.5m thick
40 – 60m deep900 – 2,500mm
Finite elementEN’sICE SPERW
Rebar 32 – 50mmConcrete 45 – 50N/mm²Bentonite/Polymers
Bidirectional jacksThermal profiling
Deep foundations – progressive development
Notes of presentation to YGG 11.04.2017
12/04/2017
17
Institution of Civil EngineersJohn Mitchell Lecture
Institution of Civil EngineersJohn Mitchell Lecture
1985 2015
Retaining walls
Bearing piles
Design analysisand codes
Materials
Testing
25 – 35m deep1.0 – 1.2m thick
30 – 40m deep900 – 1,500mm
Spring stiffnessBritish StandardsFPS
Rebar 25 – 40mmConcrete 30 – 40N/mm²Bentonite
Reaction pilesSonic coring
30 – 50m deep1.2 – 1.5m thick
40 – 60m deep900 – 2,500mm
Finite elementEN’sICE SPERW
Rebar 32 – 50mmConcrete 45 – 50N/mm²Bentonite/Polymers
Bidirectional jacksThermal profiling
Deep foundations – progressive development
Notes of presentation to YGG 11.04.2017
12/04/2017
18
Institution of Civil EngineersJohn Mitchell Lecture
Institution of Civil EngineersJohn Mitchell Lecture
Notes of presentation to YGG 11.04.2017
12/04/2017
19
Institution of Civil EngineersJohn Mitchell Lecture
Why do problems get repeated?
Generational cycles and missing knowledge
Possible solutions and best practice
Risk and cycle of re-learning
Institution of Civil EngineersJohn Mitchell Lecture
Each “generational cycle” our capability moves on– improved analysis tools– updated specifications and standards– better training– more advanced machinery and
technology
Why do we repeat past lessons?
Risk and cycle of re-learning
Notes of presentation to YGG 11.04.2017
12/04/2017
20
Institution of Civil EngineersJohn Mitchell Lecture
Rediscovering concrete
Institution of Civil EngineersJohn Mitchell Lecture
Analysis
Codes and standards
Buildability trials, research & full scale monitoring
Industry collaboration
Knowledge accessibility
People factors
Risk and cycle of re-learning – possible solutions
Notes of presentation to YGG 11.04.2017
12/04/2017
21
Institution of Civil EngineersJohn Mitchell Lecture
Projects will increase in complexity – the ground will continue to challenge and surprise
To manage risk we need to maintain a good balance between analytical capability, buildability and relevant codes & standards
Knowledge can easily become hidden requiring later re-discovery
Trials, full scale monitoring and research are all important in providing data to validate and calibrate incremental progress
Developments in foundation engineering – a personal perspective
Institution of Civil EngineersJohn Mitchell Lecture
BGA and ICE for the recognition provided in awarding the John Mitchell Medal
Current and former colleagues in Cementation Skanska and Skanska UK, including Rab Fernie, David Greenwood and the late Ken Fleming
Opportunities and motivation provided whilst at University of Surrey and University of Oxford
The many industry collaborators met through Federation of Piling Specialists, CIRIA and BSI in developing best practice
Acknowledgements
Notes of presentation to YGG 11.04.2017
12/04/2017
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Institution of Civil EngineersJohn Mitchell Lecture
Institution of Civil EngineersJohn Mitchell Lecture
Deep foundation construction – safety