Constructing Large Deep Caverns for a Long Baseline - Excavation Engineering Perspective

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Constructing Large Deep Caverns for a Long
Baseline-Excavation Engineering Perspective

• Chris Laughton, Fermilab

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Physics Underground

• Major projects planned..
• Excavation Cost, Time, Risk - key factors.. may
  limit project viability..
• Early accurate estimates of these factors needed
  for..
• Realistic planning - from the start
  (cost-optimized, timely-delivered, risk-managed)
• Framing/supporting critical decisions
• Aligning partner expectations
• Obtaining maintaining project funding..
• Excavation Engineers Perspective..
• Challenges in design and construction
• Opportunities
• optimization (ref NAT paper)
• Research integrated in design/construction
  process
• One Excavation Engineers perspective

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Engineering Research at DUSEL

• NSF Geomechanics Program is seeking research
  proposals in..
• Rock Mechanics,
• Geohydrology and
• Mining Engineering Research
• related to the design, construction and
  operation of the proposed Deep Underground
  Science and Engineering Laboratory facility, as
  well as preliminary work on research projects to
  be conducted at the DUSEL.
• Deadline - October 2 (rfragasz_at_nsf.org)
• (engineering research can support excavation
  design)

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Ground Rules?.. there are no rules!
Tool 1 Just a Few Industry Headlines..

• No design codes or standards.. just guidelines
  (ITA, ISRM, AFTES...)
• Engineering a natural material
• Properties/Loads vary in space time
• Systems performance vary too
• Risks inherent potentially very large
• Cost overruns/delays happen
• Memo to self Curb that Enthusiasm
• Dont oversell advantages simple on paper..
  (miner born optimist.. need site data to
  constrain that imagination!)
• Dont underplay the risks higher than most
  other construction ventures
• Seemingly minor problem can have major
  consequences
• Find a way to objectively express balance pros
  and cons.. (s t)

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Early Scope.. Early Alignment

• Pre-Project Plan
• Developed together..
• Construction Scope..
• Functional Needs Satisfied
• User Flexibility Defined
• Site Conditions realistic best guess
  (w/variability)
• Construction Concepts
• (case history references)
• Construction Resources (/t)
• Methods Means (MM)
• Supporting Contracts
• Integrated Plan (Tech./Convent.)
• Project Benchmarking
• Affordability?
• Early trade-offs, descopes
• Timeliness?
• Design and research priorities
• Contingency plan (/t) with realistic worst-cases

Site Investigation
Operation
3 Years
Master Schedule for 1,000,000 cubic meter Cavern
Project Similar Site Case History (Granites and
Gneisses) Underground Oil Storage
More User Flexibility.. More Options (MM Faster,
Cheaper, More Reliable)
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Underestimating the Underground

• Estimates are problematic..
• Unit costs vary by orders of magnitude
• Early independent estimates (schedule cost and
  contingency).. a good move
• Simulate balanced bid conditions..
• Complete scope / basis of estimate
• Consistent with likely terms/conditions
• Improve partner/sponsor confidence
• Ref. Diablo Canyon (23M 30)..
• Burdened Labor 10.4 M
• Permanent Materials 1.6 M
• Construction Expenses 3.3 M
• Equipment 2.7M
• Mark-Ups (Profit/Bond) 5.0 M
• Ref. Braidwood (26M 40)
• Time/Cost 21day/10-12k, w/reviews
• Poor Estimate High Contingency
• In setting contingency consider Team Skills,
  Estimating Procedures etc..

The only kind of estimate that is worth anything
is the one that is clearly defined on paper and
bears the signature of the author. J.S. Redpath
(1980).
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Underground Contingency starts at 15

• Geo-uncertainty in construction.. roads,
  foundations, cuts, tunnels
• In UK, road building (shallow depth/well-understo
  od/easily-studied geology) the average claim
  level is 14 (Ref. NCE, 4/18/96).
• If road claims average 14.. imagine what can
  happen underground, when excavating WITHIN a less
  readily-defined geology..
• Geo-contingencies can be 100 especially when
  geo-optimism is unconstrained by hard data and
  where the engineering is challenging.. even
  good rock masses behave badly (local
  soil-like/overstress/tension zones..)
• Contingency (/-) - not just geo-problems to
  consider..
• Estimating accuracy even the best estimates are
  still just estimates..
• Scope creep during design (add/change.. billable
  hours construction s)
• Competition at bid time supply-demand
  (pre-qualification a good idea)..
• Bidders contingencies.. perception of contract
  fairness
• Management costs extra problems billable
  hours (Ref. Civ Eng 04/98)
• Of course there are ways to reduce cost and limit
  contingency..

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But First.. Site Investigation

• No substitute for site-specific data.. s
  well-spent
• But phasing recommended..
• 1. Site-wide delineation of zones of bad ground
  (avoid and, if necessary, investigate how bad)
• 2. Identify, prove-out remaining sites (whole
  life)
• Pre-investigation design work subject to major
  change once investigation findings are in..
• Re-site/re-align/re-design.. re-assess viability!
  
• Cant confidently optimize before investigation
  avoid spending too many design too early
• RD - Geophysics/3-D weak zones delineation
  etc..

Use the Best The first stage should be directed
and at least in part performed by those with the
broadest understanding of the objectives, the
conditions, the likely construction methods as
well as engineering geology. Loofbourow (1979).
Make it Count Too many site investigations for
tunnels comprise a regular pattern of boreholes,
a conventional package of tests and a sigh of
relief when it is all over. Muir Wood (1972).
ITA Guidelines
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Toolbox Top Ten

• Once an early baseline is defined and a modicum
  of site-specific data gathered there are
  opportunities to OPTIMIZE the plans during design
  and construction..
• 1 Improving Stability
• 2 Optimizing for Value
• 3 Learning from Others
• 4 Streamlining Structures
• 5 Evaluating Materials
• 6 Integrating Safety
• 7 Interfacing with Industry
• 8 Partnering with Communities
• 9 Awarding Contracts
• 10 Reducing Risk
• The sooner a scope is /- agreed-on and
  objectively evaluated the better the results..
  Cost Influence Curve

Ability to Influence Final Cost over Project Life
CII 34-2
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1 Improving Stability

• Hard Rock - a complex material
• No standard properties/analyses
• Optimization Requirements..
• Site-Specific Parameters
• Delineate Faults/Shears (soil-like)
• Stresses (overstress/tension)
• Mass Structure (dense/weak in shear)
• Water Flow/Pressure
• User Needs and Flexibilities
• In Siting.. 3-D Contact/Feature Map
• Avoid the bad
• Identify/prove-out remaining sites
• In Design.. main considerations
• Size (Span, Height) Orientation relative to mass
  structure
• Shape, Orientation relative to stresses (not
  size)
• Spacing? stress/blast consideration
• RD Opportunities.. Real-time, discrete
  element/support models

Scale Independence
Scale Dependence
High Stress-Hard Rock Stability Factors
To Counter Stress-Driven Instability
High Horizontal Stresses.. Shape Mitigation
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2 Optimizing for Value

• Technically, often more than one acceptable
  solution (flexibility)..
• Construction engineers best placed to offer
  guidance. Consult those with..
• Recent, local experience
• Ground familiarity
• Up-to-date data on costs, speed, reliability for
  different solutions
• Economies of scale
• Contract strategies
• Seek-out multiple POVs
• Ref. NuMI Reviews for
• Constructability..
• Value Engineering..

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3 Learning from Others

• Benefit from experiences/ideas of others
  (cheap-most relevant)
• Colleagues shared design criteria
• Creighton, Gran Sasso, Kamioka, Pyhasalmi, Soudan
  etc..
• Industry similar design criteria
• Hydroelectric, Oil/Gas Storage, Etc.
• Experiences Not to be Repeated
• Arrowhead (draw-down), Big Dig (quality..
  fatalities), Ertan (burst.. fatalities) Sound
  Transit (cost), Holansas (contamination)
• Larger, Costly, Riskier Excavations..
• ideas/concepts
• RD Opportunities case history data base..
  engineered systems performance

Rib-In-Roc Concept
Gran Sasso Early High Stress Concept
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4 - Streamlining Structures

• Why line 200MPa-Strong Rock with 40MPa
  Concrete?
• Thick cast-in-place lining in blasted hard rock
  maybe ineffective / completely redundant
• Better Options?
• Mitigate against fracture by pre-reinforcement of
  blocky-masses
• Mitigate against overstress by tough thin
  skins - provide for seal and burst containment

thin e.g shotcrete cm not dm
Learn from the earlier/smaller excavations..
RD Opportunity for risk reduction
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5 Evaluating Materials

• Cost-Optimized/Quality Assured
• LEP waterproofing on rough surface
• In Molasse drained composite liner
• In Jura pressured composite liner
• QA-able, repairable, point-anchored,
  double-sealed HDPE
• NuMI QA-able Decay Pipe Shielding
• Low-strength, high-density flowable fill cheap
  alternative to concrete
• A mining industry technology
• Rock Insulation
• Cooler Air to Laboratories ..
• Rock wall freeze-thaw protection (ref. Glomheden
  Lindblom, 02)
• Evacuation/Containment in Chimneys
  (Raise-Bored.. Remote sprayed See 6)
• RD Opportunities LNG in LRC..

CERN Plaine
CERN Jura
FNAL NuMI Shielding Fill
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Skallen Pilot Project Underground Caverns Natural
Gas Storage operating since 2004 (thermal
expansion/contraction)
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6 Integrating Safety

• Safe Underground ..a Necessity
• Relatively hazardous work place dark and noisy,
  confined with heavy equipment, fall of ground
  potential, dust exposure.. added challenges NOT
  excuses..
• The Goal is Always Zero Accidents
• During Design Construction
• Safety criteria - an integral part of the design
• Fewer workers more isolated from the work place
  (mechanization, remote operation..).. PBM
• During Operation..
• Always Two Ways to Safety (way-out/refuge)
• Separate Lab and Construction Activities AMAP
• Manage Large Volumes of Fluids/Gases Isolated
  sites with independent high-volume
  exhaust/containment systems.. (raise bore?)
• Fire Protection (Prevention/Detection/Suppression)
  
• Design for environmental improvement too dont
  just settle for the status quo

Raise Bore, ref. bergteam
Pillar Blasting Method, TUST, 96 Proposed as
safer-faster-cheaper
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7 Interfacing with Industry

• Industry interactions can be of immense value to
  all
• Many underground contractors in design and/or
  construction we can profit from their
  collective experience professional
  organizations established to promote the
  industry.. ARMA, NAT, RETC conferences..
• Establishing/Maintaining Contact is Mutually
  Beneficial
• Valuable Physics Resource - technical, practical,
  contractual, commercial
• Valuable Industry Opportunity - business
  issues/concerns (bonds, teaming)
• Opportunities to Share and Exchange Ideas and
  Experiences
• Invitations to visit.. e.g. construction/laborator
  y sites, Fermilab hosted UCA-SME in June 06..
  Physicists were not on the radar (DUSEL, ILC,
  Theta 13..)
• None of us as smart as all of us
• Better procurement practices/bid list (reasonable
  pre-quals. etc.)
• Prepare something people will want to bid on! Get
  more, better bids..
• Lobbying too?

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8 Partnering with Communities

• Work with the whole Community
• underground can capture imagination, but..
• let the neighbors know before they find-out
  (reality before perception!)
• Soudan Mine a great example of the community
  support that can be mobilized
• The Community is a Key Partner
• Broad outreach needed.. Seek advocates
  everywhere.. kids -gt old folk..
• Offer everyone opportunities to find-out whats
  happening and provide feedback.. e.g.
  hand-delivered flyers, briefings, open days..
  They are project stakeholders too
• Anticipate problems one-on-one attention
  merited in many cases.. Issues and people at each
  LEP site were so different
• Respond to any problem issue quickly, same
  dedicated staff, hotline-accessible..
• Really a question of trust hard to reestablish
  if it is lost..

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9 Awarding Contacts

• Seek-out the best talent individuals or companies
  with the best ideas..
• Braidwood Site Investigation was
  Performance-based Ref. RFP
• Daya Bay.. Competitive Designs..
• Due diligence in contract award (si, design,
  construction, CM) is your best protection
  (well-documented)..
• Define selection process (best value?)
• Review Statements of Qualification (FNAL has info
  on number of contractors on file in the library)
• Review Work Products performed for public clients
  (courtesy request)
• Follow-up on all References..
• Key for inexperienced owners where si/design
  shortcomings may only become apparent during
  construction

• Design Build a good option if the package is
  well-defined.. difficult to change later on!

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10 - Reducing Risk

• Risk Management Steps..
• 1 Recognize the risks (cant manage what you have
  not identified!!)
• 2 Avoidance always the best solution
• 3 Mitigation through design
• 4 Manage during construction..
• (checklist in risk management.. )
• Drawings inadequate.. a certain geo-uncertainty
  will remain..
• So many experts.. so little consensus
• Disputes are commonplace..
• Risks defined/allocated in text
• Specification (if.. Then..)
• Geotechnical Data Report
• Geotechnical Baseline Report
• Alternate Dispute Resolution
• Guiding principles
• Risk allocated to those best able to manage it..
  spell-out responsibilities
• Owner owns ground - pays for misbehavior

SSCL Underground Construction On-Schedule -
On-Budget
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End of the Tunnel.. Questions?

• Compared to more familiar surface-based project,
  underground projects can be relatively
• Slow (acceleration difficult..)
• Costly (time is money..)
• Risky (difficult/costly to mitigate)
• Key early planning elements are the
• Establishment of a Realistic Early Scope, Budget
  and Timeframe
• Constaint of our shared geo-enthusiasm /optimism
  with Site-Specific Data
• During Design and Construction some proven
  management tools can help
• Optimize costs
• Identify, mitigate and control risks
• Copies of reports/paers mentioned in the
  presentation can all be obtained from
  laughton_at_fnal.gov

Thanks to Fermilab and the wider Physics
Community for the opportunity to work on these
very exciting Projects..