“Fitbit for Tunnels"

Michel Boutz (SGS INTRON) & Mohammad Fotouhi (TU Delft)

• Background & problem statement

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• Tunnel program COB

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• Research program “Future proof tunnels”�
• Monitoring material degradation in tunnels

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• Outlook

Content

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Background & problem statement

27 immersed tunnels in the Netherlands (approximately 200 in the world)

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Many built in 60s, 70s and 80s and requiring major renovations in the coming years

• Old (immersed) tunnels deform, but underlying processes are not well understood

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• Older tunnels have failing joint structures that cause leakage and unexpected shutdowns

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• Quality of monitoring instruments and results is insufficient to understand the behaviour

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• Need to share knowledge in order to renovate tunnels with less hindrance and more value

Background & problem statement

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• COB network program
• Goals:

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• Three lines of development:
• Civil engineering
• Digitalisation
• Sustainability

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• Main subjects in civil line:
• Monitoring deformation of (immersed) tunnels
• Joints in immersed tunnels
• Material degradation in tunnels

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Tunnel program COB

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• Overarching project:
• Instrumentation of tunnel data

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• Digital platform:
• Collects data from monitoring tunnels (deformation, degradation)
• Makes information, knowledge and experiences traceable and easily accessible for stakeholders
• Incorporates results from research program “Future proof tunnels” (FPT)
• Is continuously adaptable, user-friendly and future-proof.

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Tunnel program COB

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• Joint research program TU Delft & COB�
• Aim: provide tunnel owners with tools to allow rational and cost-effective decisons on maintenance and renovation of structural parts of tunnels

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• Fundamental research into the behaviour (deformation, degradation) of immersed tunnels�

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Future proof tunnels

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• Make tunnels ‘intelligent’ using sensor technology, IoT & AI models to provide realtime data on condition and performance

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• Fitbit for Tunnels
• Deformation of tunnel
• Degradation of materials
• Environment, subsoil etc.

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• Timely plan preventive maintenance
• Prolong service life
• Avoid unexpected shutdowns

Future proof tunnels

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• Monitoring of deformation:
• Installed in Noordtunnel at 22 segment joints (2024)
• To be installed In Willemspoortunnel end 2024

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• Digital platform:
• Implementation started
• Completed end 2024

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Progress instrumentarium

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• Started in 2024:
• Monitoring deformation of immersed tunnels �(Ian Pierce)
• Analysis of geotechnical data (Arne de Jong)
• Material degradation in tunnels (Sebastian Kuniewski)

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• Granted:
• Deformation of segment joints
• 3D model for immersed tunnels

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Future proof tunnels, Ph.D. projects

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'How are immersed tunnels moving, and how can we most effectively capture their deformations'

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• Historic measurements were periodic over many years.
• Measurements only at immersion joints.
• Limited capture rate (3+ years between each)
• Trend to increase rate and capture cyclic effects

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PhD1 – Deformation Monitoring

(Ian) Pierce

• Research to consider
• Efficiency of instrumentation
• Longevity of instruments
• Measurement of foundation materials

'How are long-term settlements of immersed tunnels influenced'

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• Measured settlements do exceed design limitations
• Calculated using simplified 2D FEM, or 1D beam-spring models
• Resulting in leakages and tunnel shutdown

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PhD2 – Soil Structure Interaction

Leakage in Drechtunnel (Leeuw, 2018)

Arne de Jong

Research to consider

• 3D effects
• Cyclical loading �(e.g. tidal- & temperature change)
• Et cetera.

PhD5 – Monitoring material degradation

Leakage in Drechtunnel (Leeuw, 2018)

Sebastian Kuniewski

• Identify critical locations and dominant degradation mechanisms�
• Develop/select/implement sensors to detect changes in material properties (chemical, hygral, thermal, stress & strain)�
• Collect data & use AI models for interpretation�
• Basis for decisions on preventive maintenance�
• Prolong service life and avoid unexpected shutdowns due to premature failure of materials

Monitoring material degradation

COB working group “Material degradation in tunnels”

Deliverables past 5 years:�

• Fault tree tunnels
• Visible damage materials i.r.t. causes damage

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• Inventory material degradation in tunnels
• Major cause
• When & where
• Consequences & risks
• Preventive measures
• Sensoring techniques
• Forensic tools
• Repair & maintenance
• Monitoring strategies

Monitoring material degradation

Deliverables past 5 years, continued:�

• Principles & methods for protection and repair of concrete structures
• Frequency of application
• Cost & durability
• Overall rating of method

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• Inventory of sensors for monitoring material degradation in tunnels
• Environment & structure
• Concrete
• Metals
• Coatings
• 18 fact sheets: sensor type, measuring principle, test set-up, wired/wireless, signal stability, practical applicability & experience, commercial availability, references�
• All deliverables available as free download

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Monitoring material degradation

Sensor technology

Electrochemical impedance spectroscopy

Multiparameter sensor nodes

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Lab experiments and testing

Signal processing and data analysis

Two new PhD positions available

Immersion and dilation (cast) joints

How are the deformation and residual service life of immersion and cast joints (with collar construction) influenced by interactions with the external soil?

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Tunnel-ground-surrounding interaction, a 3D interaction model

How can all tunnel-ground-surrounding interactions be captured in a workable 3D model?

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Interested? Please Contact:�COB Bart Duijvestijn bart.duijvestijn@cob.nl

TU Delft Wout Broere w.broere@tudelft.nl

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Contact details

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Dr. Mohammad Fotouhi,

Lead of Material Health Monitoring Group

Section Materials & Environment

Department 3MD

Faculty Civil Engineering and Geosciences

TU Delft, The Netherlands

m.fotouhi-1@tudelft.nl

Dr. Michel Boutz

Senior consultant

SGS INTRON

Sittard, the Netherlands

michel.boutz@sgs.com

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