Transcript Presentation - Faculty of Engineering

School of Civil Engineering
FACULTY OF ENGINEERING
Earth, Wind and Fire
Barry Clarke
Introduction
• The Ground
• The Underlying Science
• Transformational Agenda
• Resilient Infrastructure
The Ground
The Ground
• Source of primary materials
• Stable platform for construction
• Protection of the environment, people and goods
• Geotechnical structures for storage and communications
Primary Source of Materials
Primary materials
• The majority of our construction materials, fuel, minerals
come from the ground.
1999
Aluminium
77
Cement
895
Clay
304
Coal
7662
Copper
25
Glass
150
Iron ore
553
Lead
Phosphate
Potash
Salt
Sand, gravel and stone
Sulphur
Zinc
14
340
44
395
21640
111
13
Oil
7782
Gas
7803
Uranium
0.25
Average American annual mineral consumption (lbs)
Primary materials
Construction materials
• UK use of sand, gravel and
cement and concrete products
• Would cover13000 football pitches
a year with concrete products a
year
• Sand and gravel equivalent to 75
thousand elephants or 54 thousand
buses would create a 500m high hill
with side slopes of 1 in 3 or fill 200
Wembley stadia
Stable Ground
Stable platform
The province of the Engineer is to control the forces of nature
and apply them to useful purposes, an object which is effected
by means of pieces of material suitably connected and
arranged. The protection of life and property from destructive
forces is accomplished by pieces rigidly connected with one
another which transmit the their action to bodies which are not
injurious. (Cotterill, 1906)
.................it is assumed that the ground is that body.
Stable ground
•
Instability caused by overloading
of soil, and earthquakes
Stable ground
•
Instability due to mass movement triggered
by erosion, earthquakes, rainfall
Stable ground
•
Instability caused by overloading
of soil, collapse of underground
caverns and degradation of
foundations
Instability due to water pressure
•
Instability due to water pressure
Stable ground?
•
A week in the life of the earth
Human and property loss
•
•
Ground movements result in delays
to construction, damage to property
and loss of human life
90% of total losses due to storms and
flooding
Construction workload
•
Current and predicted projects used to quantify skills
requirements and indicate workload over next five years
Protection
Flood and coastal protection
•
Embankments for flood protection,
coastal erosion, wetlands, and river
diversion
Defence
•
Earth has and is still being used for
defence of sensitive installations
Storage
Storage
•
Storage of waste, water,
energy, carbon and data
The Underlying Science
The ‘myths’
• The ground is made of either
rock, sand or clay
• The majority of new build is
based on sophisticated testing
techniques
Soil particles
sand
10-6 m/sec
2mm
clay
10-11 m/sec
10μm
Characterisation of Tills
Distribution of non text book soils
• Over 60% of the UK is covered
by non text book materials
Glacial till
sand
•
transported, partially weathered homogenized
sub glacial till subsequently weathered
•
weathered sub glacial till
•
deformation till
•
transported partially homogenized sub glacial
till incorporating elements of previous melt out
till or periglacial features
•
deformation till
•
fluvioglacial deposits
•
shear zones
•
transported partially homogenized sub glacial
till containing elements of bed rock
•
deformation till or lodgment till
•
rock
laminated clay
sand and gravel
laminated clay
sand and gravel
undrained shear strength (kPa)
Characterisation of glacial tills
undrained shear strength (kPa)
0
50
100
150
200
250
300
60
350
400
450
500
0
50
4
8
10
40
30
Trenter, 1997
Bell, 2000
upper red till
lower red till
lower grey till
20
12
10
14
16
0
18
0
10
20
30
20
40
50
60
70
80
90
liquid limit (%)
0.5
SCL
ISuL
ICL
0
• Creating a framework to
characterise tills and develop a
consistent approach to selection
of design parameters
-0.5
void index
depth (m)
6
upper red till
lower red till
lower grey till
plasticity index (%)
2
upper red till strength
lower red till strength
-1
lower grey till strength
reconstituted grey till strength
reconstituted red till strength
-1.5
upper red till in situ stress
lower red till in situ stress
lower grey till in situ stress
-2
10
100
effective vertical stress (kPa)
undrained shear strength (kPa)
1000
Stiffness
Seed et al (1986)
Gur from SBP tests
in calibration
chambers
0.4
0.4
earthquakes
0
0
0.8
0.8
G
Go
well designed foundations
soft ground construction
CSBP
PAF
0.4
0
-4
10
-3
10
0.4
-2
-1
10
10
shear strain %
standard tests
0
0
10
corrected Gur
cross hole Go
G
Go
0.8
corrected
resonant column
0.8
machine foundations
Gur
Go
Local strain stiffness
applied pressure kPa
Self boring pressuremeter
5000
unload reload cycle for shear modulus
4000
3000
2000
expansion curve for strength
1000
lift off for in situ stress
0
2
4
6
8
10
cavity strain %
• In situ tests allow stiffness profiles
to be directly assessed
Reconstituted glacial till
700
deviatoric stress (kPa)
600
• Tests on reconstituted tills
compare favourably with tests on
natural soils
• Sampling is less of an issue
500
400
300
200
100
Sample 1
Sample 2
Sample 3 (Drained)
0
0
100
200
300
400
500
600
200
mean stresss (kPa)
Monotonic loading - 25kPa
Monotonic loading - 50kPa
Monotonic loading - 100kPa
Best fit to peak stress for monotonic loading
Best fit to post peak strength for monotonic loading
peak stress natural samples - Stage 1
peak stress natural samples - Stage 2
peak stress natural samples - Stage 3
Best fit to Stage 1 loading of natural soils
Best fit to Stage 2 loading of natural soils
Best fit to Stage 3 loading of natural soils
180
160
140
120
t (kPa)
• Tests on reconstituted soils can be
used to produce consistent design
values
• Reconstituted soil is created from a
slurry of till consolidated to very high
pressures to create a heavily
overconsolidated material
100
80
60
40
20
0
0
50
100
150
s' (kPa)
200
250
Richmond, 2007
300
700
400
600
350
secant shear modulus (MPa)
deviatoric stress (kPa)
Reconstituted glacial till
500
400
300
200
100
200
300
400
500
200
150
100
0
0.0001
0
100
250
50
Sample 1
Sample 2
Sample 3 (Drained)
0
Sample 1
Sample 2
Sample 3 (Drained)
300
0.001
0.01
0.1
1
10
600
shear strain (%)
mean stresss (kPa)
900
normalised shear modulus
800
Sample 3 (Drained Shearing)
Sample 1 (Undrained Shearing)
Sample 2 (Undrained Shearing)
700
600
500
400
300
200
100
0
0.0001
0.001
0.01
0.1
shear strain (%)
1
10
• It is possible to measure the local
strain stiffness and obtain the design
curve from tests on reconstituted till
• The stiffness design curve is
obtained from the normalised shear
modulus
• The shear modulus is normalised by
the mean stress to provide a unique
curve
Reconstituted glacial till
• This allows cyclic load test to be carried out to
observe the degradation of stiffness with cycles
350
CTX1 20kPa; 0 - 33%; undrained; local strain
CTX2 50kPa; 0 - 33%; undrained; average strain
CTX3 100kPa; 0 - 33%; undrained; local strain
CTX4 20kPa; 0 - 66%; undrained; local strain
CTX5 50kPa; 0 - 66%; undrained; average strain
CTX6 100kPa; 0 - 66%; undrained; local strain
shear modulus/mean effective stress
300
CTX1
250
200
CTX2
150
CTX4
CTX3
100
CTX5
CTX6
50
0
1
10
100
cycles
1000
10000
Conductivity
Hydraulic conductivity
water flow
pressure
pressure jacket
1400
specimen
2.5
1200
2
head
pressure
1.5
800
600
1
flow
1.4
400
0.5
kaolin
200
1.2
0
void ratio
1.0
0
0
10
20
30
40
50
time (hrs)
0.8
upper mottled till
upper brown till
0.6
•
0.4
lower till
•
0.2
10
100
1000
effective vertical pressure kPa
10000
Governs stability of geotechnical
structures
Increasing concern because of
climate change
potential (m)
flow (ul)
1000
Thermal conductivity
heat flow
heat sink
insulation jacket
specimen
thermistor
heat source
60
constant potential
•
Applications in geothermal
energy, melting of permafrost
due to climate change,
design of future landfills
temperature (oC)
50
heat source
falling potential
40
heat sink
30
20
room temperature
10
0
0
5
10
15
20
elapsed time (hr)
25
30
35
40
Electrical conductivity
electric flow
cathode
insulation jacket
specimen
-15
negative pore water pressure
(kPa)
anode
30
0.01
5
-35
-55
0.1
1
time (mins)
10
100
1000
10000
5V
10V
15V
-75
-95
-115
20V
25V
30V
-135
-155
undrained shear strength (kPa)
-175
25
-195
20
15
•
10
5
0
0
50
100
150
effective stress (kPa)
200
250
Applications in ground
improvement, dewatering of
slurries and stabilising of slopes
The Transformational Agenda
The Transformational Agenda
• Sustainable Built Environment
• Energy generation, dissipation and storage
• Carbon Critical Design
• Climate Change Mitigation and Adaption
• Regulation/Innovation
Sustainable Built Environment
Sustainable construction
• Sustainable construction is an aim that can be achieved
through an incremental approach
• But there is much evidence that even that approach is too
slow
• Of 123 contracts reported, only 54% had a sustainability clause
• Of the top ten contracts (by value) only 6 had a sustainability clause
• Only 3.1% of total spend on catering contracts had a sustainability
clause
• 9 of the 21 Depts still do not include clauses regarding ‘Quick Win’
product standards in all contracts
BERR Mar 2008
undrained shear strength (kPa)
Zero carbon by 2016
Sustainable ground engineering
• Baseline reporting to assess risk and increase client
commitment to whole life costing and optimum designs
• Application of Eurocode to improve ground investigations to
produce reliable, optimum designs
• Better application of ground characteristics
• Balanced approach to ground energy
• Reuse of excavated materials
• Use of waste as a resource
• Reuse of foundations
Energy
Geotechnical engineering for energy
• Foundations for energy structures including wind turbines,
nuclear power stations, sea bed structures
• Storage of energy related resources including nuclear
waste, carbon, heat
• Ground energy systems
• Barrages
Geothermal energy
•
•
•
Development in technology has
enabled ground energy to be
used in UK
Regulation is required to control
expansion
Carbon reduction, sustainable
development and energy
efficiency are drivers for change
Ground energy
low to high enthalpy
geothermal
ground source
energy systems
open loop surface
water and
groundwater
abstraction/discharge
stored/recharge solar
energy and
geothermal flux from
earth core
closed loop ground
loop heat exchangers
surface water
(sea/lake/river)
geotechnical
structures
aquifer bidirectional
horizontal trenching
aquifer thermal
energy storage
vertical borehole
surface water
(sea/lake/river)
Energy systems
Carbon storage
• Carbon storage serious
short term solution
• Yorkshire is UK’s leading
region in this development
IPCC Special Report on Carbon dioxide
Capture and Storage
Carbon Critical Design
Design criteria for performance
Performance Level
Fully
Operational Life Safe
Operational
Design
Level
Frequent
Near
Collapse
unacceptable
performance for
new construction
New Orleans
1:200
Occasional
London
1:1000
Rare
Amsterdam
1:10000
Very Rare
SLS
ULS
Climate
Change
Climate
Change
Design criteria
UK Government view of sustainable development in 2000
• Social progress which recognises the needs of everyone
• Effective protection of the environment
• Prudent use of natural resources
• Maintenance of high and stable levels of economic growth and
employment
Sustainable construction 2003
• design for minimum waste
• lean construction (& minimise waste)
• minimise energy in construction & use
• do not pollute
• preserve and enhance biodiversity
• conserve water resources
• respect people and local environment
• set targets (ie monitor & report, in order to benchmark performance)
Yorkshire low carbon economy
• Yorkshire & Humber contributes 13% of the UK’s greenhouse-gas
emissions yet provides 7.5% of GVA
• Pumps approximately 90m T of CO2 into the atmosphere every year
• CO2 emissions showed a rise of 1.5% each year between 2000 and
2004, compared to a nationwide fall because of dependence on coalfired power generation compared to the national switch from coal to gas
• Companies can save an average of 1% of turnover, or £1,000 per
employee, by implementing resource efficiency measures
• The regional recycling sector is currently worth £400m
• The sea level around the Humber Estuary is predicted to rise by 82cm
by 2080
• An increase in annual flood damage of over £10m by 2080 along the
Lancashire-Humber corridor if levels of atmospheric CO2 continue to
rise, and GDP increases by between 2% to 3.5% per year
The carbon challenge
• Our sector (construction) is facing the most complex challenge it has
ever dealt with. Changing the way we design the built environment is a
phenomenal challenge, both technically, organisationally and culturally.
• Nobody knows enough today about how to solve or mitigate the carbon
issues in the products that we design. We will not get there in a single
step. We will no longer be able to design a building, and then do the
energy calculation only to find it uses too much energy. The same is
true how we design our public infrastructure, choose our materials and
procure. It will radically change the design question to something that
starts at the beginning.
(Clarke, 2009)
A carbon ‘free’ world
1999
1776
77
0
Cement
895
12
Clay
304
100
Coal
7662
40
25
1
Glass
150
1
Iron ore
553
20
14
2
340
0
44
1
395
4
21640
1000
111
1
13
0.5
Aluminium
Copper
Lead
Phosphate
Potash
Salt
Sand, gravel and stone
Sulphur
Zinc
Oil
7782
Gas
7803
Uranium
0.25
Design criteria
1
5
construction costs
maintenance costs
200 operating costs
RAEng
whole life cost assessment
and
whole life carbon assessment
Climate Change
undrained shear strength (kPa)
Climate change impact
•
•
•
•
•
•
•
•
Exponential increase in floods and droughts
Increased frequency of extreme events
Cubical increase in storm damage
Quadratic increase in coastal damage
200 m people, 2m km2 and $1trilion assets within 1m of sea level
22 of top 50 cities under threat
200m people will migrate because of increase in temperature and loss of land
Changes in soil conditions threaten stability of infrastructure (drought, rising
groundwater, melting permafrost)
(Stern, 2005)
BIONICS
JOB TITLE :
Flac\Shetran comparison (no overland flow)
(*10^1)
FLAC (Version 4.00)
1.000
LEGEND
10-Aug-06 13:03
step 24878487
Cons. Time 2.8382E+08
-1.333E+00 <x< 2.533E+01
-1.333E+01 <y< 1.334E+01
0.500
Max. shear strain increment
1.00E-02
2.00E-02
3.00E-02
4.00E-02
0.000
Contour interval= 1.00E-02
Grid plot
0
5E 0
-0.500
-1.000
Newcastle University
U.K.
0.250
• Climate change will lead to instability
of infrastructure due to pore
pressure changes and changes in
vegetation
• BIONICS is an EPSRC funded
project to study this effect
(Glendinning, Davies and Hughes, 2008)
0.750
1.250
(*10^1)
1.750
2.250
Climate Change Act 2008
An Act to set a target for the year 2050 for the reduction of targeted
greenhouse gas emissions; to provide for a system of carbon budgeting; to
establish a Committee on Climate Change; to confer powers to establish
trading schemes for the purpose of limiting greenhouse gas emissions or
encouraging activities that reduce such emissions or remove greenhouse
gas from the atmosphere; to make provision about adaptation to climate
change; to confer powers to make schemes for providing financial
incentives to produce less domestic waste and to recycle more of what is
produced; to make provision about the collection of household waste; to
confer powers to make provision about charging for single use carrier
bags; to amend the provisions of the Energy Act 2004 about renewable
transport fuel obligations; to make provision about carbon emissions
reduction targets; to make other provision about climate change; and for
connected purposes.
Climate change in Yorkshire, 2050
• Annual average temperatures between 1.8°C - 1.9°C
• Summer average temperatures up between 2.1°C - 2.5°C
• Extreme hot temperatures up between 2.8°C - 3.2°C
• Annual rainfall down by approximately 6%
• Winter rainfall up by 12 – 17%
• Summer rainfall down by 22 – 26%
• Winter snowfall down by 54 – 68%
• Annual average wind speeds down by approximately 1%
• Winter average wind speeds up by approximately 1%
• Soil moisture annual average down by around 5 – 11%
• Mean sea level increase of 0.35 metres, with more severe surges.
The Innovation Agenda
The geotechnical cycle
application
full scale testing
• The geotechnical cycle is incremental
• Change has been driven by improvements in
instrumentation, scientific developments,
numerical methods, monitoring, failure and
products and processes
characterisation
modelling
Drivers for change
Driver
Targets
Policy
Carbon Emissions
Water Reduction
Waste Reduction
Energy White Paper
Water shortage
and continuing
increase in population
Energy White Paper
Zero carbon by 2016 for new build
80% reduction in existing build by 2050
Reduction of 25% of
water consumption by
2020 from the current
water usage of 150
litres per day.
50% reduction in waste
disposed from
Construction
Projects by 2012
Climate Change Act
Code for sustainable homes
Code for Sustainable Communities
Committee on Climate Change
Building a low carbon economy
Waterwise and Govt
Water Reduction
Targets
Waste and Resources
Action Programme
(WRAP)
New Build
Zero carbon
housing
by 2016
Zero carbon
schools
by 2017
Zero carbon Public
Buildings by 2018
Existing Stock
80% reduction of
1990 CO2 levels
by 2050
Population
+2.8m in UK
1996-2016
200m
population
migration
by 2050
Innovation
Product
e.g. Characterisation and modelling
of the ground
e.g. Retrofit renewable
energies
e.g. Offsite fabrication linked into
design process where vertical
and horizontal integration
takes place.
e.g. Remote excavation
such as pipe jacking
e.g. Prefabricated
components within a
project such as tunnel
formers
People
Process
e.g. Ground improvement
techniques
(ConstructionSkills, 2009)
Construction continuum
Industry activity
Major international contractors and consultants
Training and Education
Fusion
(ConstructionSkills, 2009)
Regional contractors and consultants
National contractors and consultants
Large SMEs
Specialists contractors and consultants
Offsite
activity
Modern Methods
2000+
Traditional construction
1920 - 2000
Built heritage
Pre 1919
Graduates
Professional development
Apprentices
Manufacturers
New credit system to meet changing needs
indentified by SSCs
Existing qualifications to meet existing
needs and expanded to address
carbon agenda
Heritage skills
School of Civil Engineering
FACULTY OF ENGINEERING
Institute of Resilient Infrastructure
The hidden lifelines
Skirrid Fawr, S Wales a green and pleasant land, (Venables 2008)
The lifelines
73
Resilient infrastructure
• Those lifeline systems that will be able to survive and
perform well in an increasingly uncertain future.
• Existing and new infrastructure becoming more adaptable;
and, being created, designed, built, operated, and / or,
disposed of in current, new and emergent futures.
• The environmental, economic and social impact associated
with demolition, disposal and replacement of infrastructure
is comparable to the impacts created during its operational
lifetime.
• Preserving and extending the life of infrastructure - i.e.
enhancing its resilience - is the best way to maximise its
sustainability and help protect our climate, resources and
way of life.
Institute of Resilient Infrastructure
• The remit of the Institute covers sectors
• dealing with ‘civil-engineering structures’, for example, roads,
railways, airports, flood defences, ports and harbours, water
treatments plants, oil, gas and power plants and the utilities’
distribution infrastructures, and
• associated with ‘building-structures’ for example, schools, healthcare
facilities, manufacturing plants, retail and industrial outlets,
commercial offices, housing developments, and different types of
government buildings.
• Short, medium and long term requirements
Investment Strategies
Asset Management
Managerial & Supply
Structures
New Infrastructure
Existing Infrastructure
Developed
Countries
Create
Grand
Challenges
Categorising Infrastructure
Developing
Countries
Drivers for Change
Institute of Resilient Infrastructure
Existing
Technologies
Engineering
Solutions to
Infrastructure
Provision
‘Heritage’
Technologies
Institutional Structures
Policy Implications
New
Technologies
Typologies
of
Response
‘Old’
Technologies
Conclusion
Opportunities
•
•
•
•
•
•
•
Energy
• Efficiency through improved geotechnical processes
• New distribution networks and storage systems
• Barriers and barrages
Protection and enhancement of sinks and reservoirs of greenhouse gases
• Underground caverns
• Storage in strata
Protection of environment
• Flood control
• Ground water protection
• Stabilisation of infrastructure
• Future proofing landfill
Promotion of sustainable forest management practices, afforestation and reforestation;
• Landslide management
Promotion of sustainable forms of agriculture;
• Sustainable groundwater water supply
• Water storage systems
Renewable forms of energy,
• Ground as a source of energy
• Innovative geotechnical structures
Waste
• Reuse
• Management
Future scenarios
Let it Rip: Economic growth and
consumerism pursued at the expense of
environment. The effects of climate change
are well advanced and there is intense
competition for increasingly scarce natural
resources, the consumption of which has led
to alarming levels of waste and C02
emissions. A heavy reliance on technology to
combat climate change has increased the
wealth gap between rich and poor nations.
Technofix: Economic growth remains an
important political objective, but state
intervention promotes development of green and
innovative technology, internalises external costs
and redistributes of wealth. International
cooperation ensures this is not an economic
disadvantage. Choice and innovation still
blossom. Following the global recession, London
is no longer an international financial centre
(nowhere is), but the UK is now a world leader in
green technology
Fortress Mentality: A closed economy
without imports and exports or a transient
migrant workforce forces re-localisation,
generating a self-defence mentality. Cycling
is the dominant modal share. Energy poverty
reflects economic poverty as people lose their
jobs and their homes. Exhaustion of crop and
animal supply as people fight over resources.
Carbon Rationing: People's lifestyles are
determined by a strict and enforced scheme of
carbon consumption control, imposed by UK
central government and overseen by the Carbon
Commissar. Carbon is the new currency.
Horizons and mobility have shrunk to an extent
that people live a more local and communityfocused lifestyle.
(Arup, 2009)
Speed of change
• Development of
canal system over
sixty years
• Development of rail
system over sixty
years
Acknowledgements
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