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

1. Constructing Large Deep Caverns for a Long Baseline-Excavation Engineering Perspective Chris Laughton, Fermilab Laughton – Fermilab - NNN’06

2. 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 Engineer’s Perspective.. • Challenges in design and construction • Opportunities • optimization (ref NAT paper) • Research integrated in design/construction process • One Excavation Engineer’s perspective… Laughton – Fermilab - NNN’06

3. 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@nsf.org) (engineering research can support excavation design) Laughton – Fermilab - NNN’06

4. 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 • Don’t oversell advantages: simple on paper.. (miner = born optimist.. need site data to constrain that imagination!) • Don’t 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) Laughton – Fermilab - NNN’06

5. Early Scope.. Early Alignment Site Investigation Operation • 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 ($/t) • Methods & Means (M&M) • Supporting Contracts • Integrated Plan (Tech./Convent.) • Project Benchmarking • Affordability? • Early trade-offs, descopes • Timeliness? • Design and research priorities • Contingency plan ($/t) with realistic worst-cases ~ 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 (M&M Faster, Cheaper, More Reliable) Laughton – Fermilab - NNN’06

6. Underestimating the Underground “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). • Estimates are problematic.. • Unit costs vary by ordersof 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.. Laughton – Fermilab - NNN’06

7. Underground Contingency starts at 15% • Geo-uncertainty in construction.. roads, foundations, cuts, tunnels • In UK, road building (~shallow depth/well-understood/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.. Laughton – Fermilab - NNN’06

8. 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! • Can’t confidently optimize before investigation avoid spending too many design $ too early R&D - 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 thebroadest 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 Laughton – Fermilab - NNN’06

9. 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 Laughton – Fermilab - NNN’06

10. 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 • R&D Opportunities.. Real-time, discrete element/support models Scale Independence Scale Dependence High Stress-Hard Rock Stability Factors To Counter Stress-Driven Instability Laughton – Fermilab - NNN’06 High Horizontal Stresses.. Shape Mitigation

11. 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.. Laughton – Fermilab - NNN’06

12. 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 • R&D Opportunities – case history data base.. engineered systems performance Rib-In-Roc Concept Laughton – Fermilab - NNN’06 Gran Sasso – Early High Stress Concept

13. 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.. – R&D Opportunity for risk reduction Laughton – Fermilab - NNN’06

14. 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) • R&D Opportunities – LNG in LRC.. CERN Plaine CERN Jura FNAL NuMI Shielding Fill Laughton – Fermilab - NNN’06

15. Skallen Pilot Project Underground Caverns Natural Gas Storage operating since 2004 (thermal expansion/contraction) Laughton – Fermilab - NNN’06

16. 6 – Integrating Safety Raise Bore, ref. bergteam • 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 don’t just settle for the status quo Pillar Blasting Method, TUST, ’96 Proposed as safer-faster-cheaper Laughton – Fermilab - NNN’06

17. 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/laboratory 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? Laughton – Fermilab - NNN’06

18. 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 -> old folk.. • Offer everyone opportunities to find-out what’s 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.. Laughton – Fermilab - NNN’06

19. 9 – Awarding Contacts • Design & Build a good option if the package is well-defined.. difficult to change later on! • 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 Laughton – Fermilab - NNN’06

20. 10 - Reducing Risk • Risk Management Steps.. • 1 Recognize the risks (can’t 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 Laughton – Fermilab - NNN’06

21. 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@fnal.gov Thanks to Fermilab and the wider Physics Community for the opportunity to work on these very exciting Projects.. Laughton – Fermilab - NNN’06