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Harald Wagner_Construcción de túneles, métodos convencionales; EL ESPACIO SUBTERRÁNEO OPCIÓN DEL FUTURO.TRANSCRIPT
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El espacio subterrneo opcin del futuro WTC CIUDAD DE MXICO, 8 10 OCTUBRE 2014
SESION 4 Metodos Convencionales
Harald Wagner, ITA EXCO Expert 8 Octubre, 2014 17:30 18:10
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CTM Structures Strategic Approach
Introduction
Geotechnical Principles
Conceptual Design Phase
Preliminary Design Phase
Tender Design Phase
Final Design Phase
Geotechnical Design
Geotechnical Construction
Geotechnical Report
Baseline Construction Plan
Safety Management Plan
Monitoring
Risk Management
Extraordinary Support
Conclusions
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1. Introduction
Classical CTM construction stages for infrastructure tunnel (1998)
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WDC - CTM Station (10.000 trees to the future)
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CTM Technology
Ground surrounding the Tunnel is considered to be a load bearing structure as full or part of support.
Ground has to be kept in its integrity.
Ground and Ground Behaviour determine basic and additional Support.
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Geotechnical Baselines
Baseline 1 Equilibrium Shortly after excavation and
installation of support, the new ground
Equilibrium shall be achieved!
Baseline 2 Safety
Tunnel lining Safety during and after construction needs to be defined until
the end of design life !
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Geotechnical Model
Soil
Rock
0
20
60
40
80
100
100
80
60
40
20
str
ess
r0/1
00
tim
eT
4 5 6 7 8 9 10 deformationr20 50
Scheme of r r Curve(after Fenner and Pacher)
Soil
Rock
Radial deformation governing size of excavation section
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CTM Metro Stations
Specific advantages of Conventional Mining for Station Design near sensitive and valuable historical Structures
Mined Method allows limitation of number of stress shifts, as every stress shift reduces natural bearing capacity of ground.
Evaluation of different Design Alternatives leads to decision for Station Configuration.
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Mined Station Advantages
Virtually unlimited space in the configuration and design of the underground station.
Minimize settlements and deformation of surrounding ground.
Technology to monitor and to limit deformations within calculated prediction.
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Metro Station Evolution Phase I 1974 - 1993
1974 - 1976 Subway Bochum, Germany
1975 - 1977 Subway Nuremberg, Germany
1977 - 1982 Subway Munich, Germany
1981 - 1985 Metro Mexico, Mexico
1991 - 1995 Subway Munich, Germany
1986 - 1991 Station Washington, USA
1992 - 1993 Subway Milano, Italy
1991 - 1992 Metro Los Angeles, USA
1993 - 1995 Subway Paris, France
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Metro Station Evolution Phase II 1994 - 2005
1992 - 1995 Metro Washington, USA
1994 - 1995 Metro Lille, France
1998 - 2000 Subway San Juan, Puerto Rico
2000 - 2000 Metro New Delhi, India
2000 - 2001 Sound Transit Seattle, USA
1998 - 2001 Subway Stuttgart, Germany
1999 - 2002 East Side Access New York, USA
1998 - 2004 Metro Budapest, Hungary
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Metro Bochum Germany 1976
Metro Station Berliner Platz worldwide 1st NATM Metro Station
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Metro Nuremberg Germany 1977
Metro Station Lorenz Church - separated tubes near historic towers
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Metro Munich Germany 1981
Theresienwiese Station Prototype Multiple Drift NATM Excavation
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Metro Mexico Mexico D.F. 1982
Linea 3 Sur - Estacion San Joaquin
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Metro Washington DC USA 1991
Fort Totten Station - 1st soft ground NATM Station in North America
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Metro Budapest Hungary 2004
Combination of Station Concepts CTM/NATM, C+ C, TBM
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BLE CONTRACT 1- Bangkok 2008
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Wang Burapha Station (CTM Staked Station)
C&C
TBM
NATM
PHASE 2
PHASE 1
PHASE 3
TRIPLE PHASE
RISK CONTROL
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Sanam Chai Station (CTM Binocular Station )
NATM
PHASE 2
PHASE 1
PHASE 3
TBM
C&C
TRIPLE PHASE
RISK CONTROL
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Bangkok BLE Elementary Lessons
Wang Burapha and Sanam Chai Stations were designed using
Conventional Tunnelling (CTM/NATM) and constructed using hybrid
solutions.
Experience Contractors proposed to use Roof Piping due to lack
of technological experience and claiming equivalency.
Screening Contractors shall be screened upon implemen- tation of
Qualification Criteria for capabilities in Tender Documents.
Cost Comparing Environmental Impact between different
underground structures, conventional based concepts prevail in urban
infrastructures.
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2. Geotechnical Principles
Base theory of CTM/NATM is to view the ground around and on top of the tunnel not only as a load, but also as a load-bearing element of support.
Ground reactions as lining deformations and lining pressures are measured. The stability of the excavation is confirmed by frequent monitoring.
Depending on project conditions (e.g. shallow soft ground tunnel, deep rock tunnel) and results of geotechnical measurements, requirement for Rapid rigid Support or Slim deformable Support is identified.
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Contractual Principles
Contractual arrangement requires the most economical type
and amount of support installation in the tunnel.
Ground Classification related to stand-up time of an
unsupported section of the tunnel was the original approach
to conventional tunnel construction.
On base of experience and contractual framework, applicable
ground class needs to be agreed between Contractor and
Engineer at excavation face.
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Strategic Development
Project Development of a tunnel shall be subdivided into following stages
conceptual design
preliminary design
tender design (detail design, phase 1)
construction design (detail design, phase 2).
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3. Conceptual Design Phase
Scope and verification of design
Selection of preferred alignment from several
alignment studies
Geological and hydrological information to develop
geotechnical characteristics
Validation of anticipated construction method
including environmental aspects
Conceptual cost estimate
Conceptual construction schedule
Conceptual ventilation scheme
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4. Preliminary Design Phase
Target to receive approval from the client
Evaluation of site investigation and lab test results
Identification of portal locations and structure
Development of typical cross sections
Decision on tunnel advance methods
Tunnel waterproofing and drainage concepts
Construction concepts, water and power supply,
location of construction roads and muck depots
Detailed construction programme
Revised cost estimate
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5. Tender Design Phase
Tender design includes:
Detail design of all structures and incorporation of latest project developments, results of additional site investigations and requirements by the authority.
Update of geotechnical prognosis, support measures drawings, distribution of support classes, detailing of auxiliary construction methods and provision of information as required by the national standards and guidelines.
Scope of tender design includes details of works in order to make exact pricing of each work item feasible.
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6. Final/Construction Design Phase
Construction design includes:
The adaptation of the detail design to the particular requirements of the excavation and support methods selected for construction and to the geological/geotechnical conditions encountered in situ is a particular aim of conventional tunnelling contracts conditions found on site.
The production of design drawings used for the construction (e.g. formwork drawings, reinforcement drawings and schedules, fabrication drawings etc.).
Scope of construction design requires detailing of works described in the tender stages in order to make construction feasible.
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7. Geotechnical Design
Design has to contain BCP (Baseline Construction Plan. It shall describe expected ground conditions, assumptions, and boundary conditions the design is based on.
BCP shall contain Statements describing which measures cannot be modified during construction
BCP shall contain Criteria for possible modifications and adjustments during construction.
Results of all phases of geotechnical design have to be summarized in a Geotechnical Report.
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Steps in Design
Step 1: Determination of Ground Types
Step 2: Determination of Ground Behavior Types
Step 3: Determination of Excavation & Support
Step 4: Geotechnical Report BCP - Plan
Step 5: Determination of Excavation Classes
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8. Geotechnical Construction
Geotechnical rock mass parameters have to be collected, recorded, and evaluated to determine the Rock Mass Type.
Monitoring data together with the rock mass type shall determine the Rock Behaviour Type to be determined.
Geotechnical Design and Baseline Construction Plan have to be continuously updated based on findings on site.
Excavation & Support have to be determined based on criteria laid out in BCP
(Baseline Construction Plan) and SFP (Safety Management Plan).
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Steps in Construction
Step 1 Verification of Ground Type
Step 2 Verification of Ground Behaviour Type
Step 3 Verification of Excavation and Support
Step 4 Verification of System Behaviour
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9. Geotechnical Report
Summary of Results of geologic/geotechnical investigations, interpretation
Rock Mass Types description, associated key parameters
Rock Mass Behaviour Types description, influencing factors, analyses performed, geotechnical model as base for Behaviour Type
Excavation & Support determination, scenarios, analyses applied, results
BCP (Baseline Construction Plan), excavation class determination, distribution along the alignment
Detailed Specifications to the BCP, System Behaviour, measures on site, warning criteria and limits, etc.
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10. Baseline Construction Plan
BCP summarizes Geotechnical Design to following information
Geological model, distribution of Rock Mass Types and Behaviour Types
Sections, where specific requirements for construction have to be observed
Fixed excavation and support types (round length, excavation sequence, overexcavation, invert distance, support quality and quantity, ground improvements, etc.)
Measures to be determined on site (presupport, face, face support, ground improvement, drainage, etc.)
Description of System Behavior (behavior during excavation, deformation characteristics, utilization of supports, etc.)
Warning criteria and levels, as well as remedial measures according to the safety management plan
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11. Safety Management Plan
SMP shall contain following topics
Design Concept for determination of excavation & support
Criteria for Assessment of Stability based on the knowledge of ground conditions during design
Monitoring Concept with all technical and organizational provisions to allow a continuous comparison between the expected and actual conditions
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Safe Crown Excavation & Face Support
BEG Tunnel - Lot 5, Austria
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Safe staggered Bench Excavation
BEG Tunnel - Lot 5, Austria
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Full Cross Section Excavation
BEG Tunnel - Lot 2-1, Austria
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Installation Waterproofing Membrane
BEG Tunnel - Lot 5, Austria
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Invert Arch Reinforcement
BEG Tunnel - Lot 5, Austria
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Inner Lining Reinforcement
BEG Tunnel - Lot 5, Austria
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Arch & Invert Final Lining
BEG Tunnel - Lot 5, Austria
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12. Monitoring
Routine tunnelling shall monitor following State of the Art of Data Evaluation
Tunnelling through Poor Ground shall provide experience from monitoring of problems and solutions.
Proper modelling in design, continuous & adequate monitoring of ground/support interaction forms base for on site decisions.
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Monitoring in Construction
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Deflection Monitoring
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Displacement History Plots
Value of Information from plots
Assuming continuous face advance, displacement rate over
time has to decrease
Displacement acceleration indicates destabilisation, unless
there are ongoing construction activities in the monitored
tunnel section (e.g. bench and invert excavation, or shaping
activities)
Stabilisation is reached after bench and invert excavation
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Displacement History
Typical displacement history diagram, showing expected behaviour and indication of destabilisation
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Final Displacement
Final displacements extrapolated from few readings, using
previous experience and including the actual geological situation
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Deflection Curve
Value of Information of deflection curves
When showing several deflection curves on the same plot,
comparison of displacements along tunnel is possible
Information on the longitudinal extent of tunnel
deformation behaviour is provided
Trends of relative decreasing or increasing ground
behaviour can be verified
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Deflection Curve Extrapolation
The extrapolation of deflection curves to the tunnel face and the addition of the resulting
difference ("pre-displacements") to the measured values
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Deflection Curve Plot
Typical plot of deflection curves when excavation approaches a "weak" zone
(schematically)
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Trend Lines
Value of Information
Trend lines provide an overview of displacement development along tunnel axis, used for extrapolation beyond face
Trend lines used to determine appropriate support type and quantity for comparison of similar deformation behaviour.
Trend lines with increasing displacement tendency can indicate critical situations and must be analysed
Trend line shows settlement beyond face.
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Trend Line of Settlement
Trend line of settlement when tunnelling in homogeneous rock mass and
when passing a fault zone (schematically)
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13. Risk Management
Risk Register serves for Risk Identification
Different Risks in Design & Construction, e.g.
inadequate design, unforseen ground conditions
Risks are to be prioritized and quantified
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Risk Analysis
RA takes measures to avoid double risk counting
RA takes account of correlation between risk types
Quantification of potential cost overruns reflects possibility of increased staff costs
Correlation between unforseen ground condition cost and risk of contractual claims should be estimated
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Risk Management Steps
Step 1 Establish objectives and risk appetite
Step 2 Risk identification
Step 3 Risk classification
Step 4 Risk allocation
Step 5 Risk assessment, impact & quantification
Step 6 Identification of mitigation procedures
Step 7 Preparation and update of risk register
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14. Extraordinary Support - Samples
Standard Support
Measures are contractually to be installed all along
the length of the tunnel.
Means & Methods should be specified and
designed.
It should be demonstrated when and how
additional support measures respectively
contingency support measures shall be installed.
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Additional Support
Designed and specified ground conditions are requiring
standard support measures, in order not to exceed
1.0 x dcrit.
It dcrit represents a threshold value, which is on the very
safe side, for the purpose of defining the value requiring
additional support measures.
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Deformation related Support
RE
LE
VA
NT
CR
OS
S S
EC
TIO
N
FO
R M
EA
SU
RE
ME
NT
ACTUAL
DEFORMATION
STRESS RELIEVE
1.0
d =
100%
1.4
d
70%
D/2AL
90%80%
LONGITUDINAL SECTION
0%
4'
Dcrit.
50%60% c
rit.
crit. SS
M
1.8
d
CA
SM
CIG
MA
SM
crit.
- FOR SUPPORT MEASURES SEE INDIVIDUAL DRAWINGS
LIT: ICONMIG 1988 (PAGE 1,531 ff)
ADDITIONAL SUPPORT MEASURE INSTALLATION
-d TRESHOLD DEFORMATION DEFINED TO START
- AL ADVANCED LENGTH
- CIGM CONTINGENCY IMPROVEMENT OF GROUND
- CASM CONTINGENCY APPLICATION OF SUPPORT MEASURES
- ASM ADDITIONAL SUPPORT MEASURES
NOTE: - SSM STANDARD SUPPORT MEASURES
crit.
SUPPORT MEASURES BEYOND GBR
EXAMPLE OF RELATED DEFORMATION
Time & location related deformations with support categories
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Decision Matrix
1.81.71.5 1.61.41.2 1.31.1d0.90.7 0.8No. SUPPORT TYPE
SOIL NAILING 21 (Standard)
SHOTCRETE: (10 cm) 4"
ADVANCE LENGTH (AL) 4'
VACUUM LANCES IN INVERT
DEWATERING / PROBE HOLES: 5 WELL POINTS IN TOP HEADING,
PIPE ROOF: 29 pcs, L=50' e=10'
FACE BOLTING: 9 pcs, fibre glass, L=28', in top heading
FACE SEALING: 2" (Total) fibre shotcrete
SPILING: Bar size 9, (1.0 sqin)
LATTICE GIRDERS: on 3' spacing, Type PS 95/20/30
ADDITIONAL SHOTCRETE
ADDITIONAL SOIL NAILS: for AL + 30%
ADDITIONAL SOIL NAILS: 21 (Add.) /3' for 100 % AL
REDUCED ADVANCE LENGTH (AL) 3'
SUPPORT TYPE
ADDITIONAL SOIL NAILS: For 100 % AL as required
SUPPORT TYPE
DIVIDED FACE EXCAVATION
ADDITIONAL SOIL NAILS: for AL + 50% as required
ADDITIONAL SHOTCRETE
PIPE ROOFING
FACE SEALING: 2" (Total) fibre shotcrete
FACE BOLTING: Fibre glass, L=28', in top heading
GROUTING
4b
5
4a
SUPPORT
MEASURES
CONTINGENCY2
3
1b
No.
0
1a
5
SUPPORT
MEASURES
ADDITIONAL
4a
4b
3b
3a
2
0
1b
1a
No.
MEASURES
3
2
STANDARD
SUPPORT1
0
0.80.7 1.41.2 1.3d 1.10.9 crit 1.81.71.5 1.6
0.80.7 0.9 1.1d crit 1.31.2 1.4 1.61.5 1.7 1.8
crit
CROSS SECTION
6 JET GROUTING: improvement of Qpnl
NOTES: - TUNNEL WALKER HAS AUTHORITY TO ADDITIONAL MEASURES AT ANY TIME AS REQUIRED BY FACE CONDITIONS.
- MEASURES CANNOT BE REDUCED WITHOUT CONSENSUS.
DECISION MATRIX
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Soft Ground Metro Station
Anchors Shotcrete Observational Approach Sequential Excavation Timely Ring Closure
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Flexibel vs. Stiff Approach
Flexible Approach - Ground Arch using
Anchors - Thin SF Shotcrete - Flat Dome - Top Heading Stiff Approach - Steel Ribs & Wire
Meshes - Thick Shotcrete - Tear Drop
Excavation
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Classical Binocular Soft Ground Station
Estacion San Joaquin Mexico & Fort Totten Station Washington DC
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Station Excavation Phase 3
Metro Washington Fort Totten Station
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Side Drift Excavation Phase 4
Metro Washington Fort Totten Station
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Multiple Drift Excavation
Metro Washington Fort Totten Station
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Penetrating Soldier Pile Portal Wall
Metro Washington Fort Totten Station
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Presupporting Steel Pipes
Metro Washington Fort Totten Station
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Penetrated Shotcrete Shaft
Metro Washington Fort Totten Station
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Heavy anchored, multiple drift X-Section
Sound Transit Seattle Monocular Cross Section
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Narrow Tunnels with prestressed Pillar
Parramatta Tunnel, Sydney, Australia
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Anchor Support & Multiple Drift
Ia
IIIa
IIIb
Ib
IIa IIb
Metro Budapest, Hungary
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15. CTM Conclusions
Ground is viewed as integrated element of support
Ground reactions are measured to confirm stability
Ground should be kept undisturbed
Type of support to allow most economical design
Construction decisions based on Ground Behaviour
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Disclaimer
Disclaimer a) The speakers are presenting their own personal views and are not expressing the view of any Organization. b) Papers and documents displayed or handed out during the Event are copyrighted. The participants must observe and comply with all applicable law regulations concerning the copyright.
Underground Space Option of the Future
Ciudad de Mexico, Octubre 8 10, 2014