PRIME: Proactive Infrastructure Monitoring and Evaluation · PRIME . Instrument . Solar . regulator...

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PRIME: Proactive Infrastructure Monitoring

and Evaluation

PRIME MOVERS:

Jon Chambers / Philip Meldrum / Paul Wilkinson

Geophysical Tomography Team


PRIME – What is it ?

• A new low cost – low power 4D [time lapse 3D] ground resistivity imaging system for critical zone monitoring.

• Develop a system and demonstrate the operational benefits of PRIME to potential beneficiaries including the research community, asset owners and service providers……

Critical Zones

Geohazards

Landfill / Barriers

Mining groundwater rebound

Groundwater

contamination


Electrical Resistivity Tomography (ERT) – What is it ? NON-INVASIVE

• Resistivity – the resistance of the ground to passing electrical current. Sensitive to geological variations, changes in groundwater saturation, and the presence of contaminants. (Imaging by ERT – analogous to medical imaging)

• Why use ERT?

• Volumetric information

• Non-invasive

• Rapid

• Composition

• Moisture content

Material Resistivity (Ohm.m) Clay Low Sand and gravel Moderate Concrete High Granite Very high

Medical imaging

Geophysical

imaging


Field ERT – What does it look like ?

Resy Array: 64 electrodes x 0.5 m electrode spacing

BIONICS, Hexham


Field ERT – What does it look like ?


GSM router

Antenna

Batteries

PRIME Instrument

Solar regulator

Solar array, 20W

Sensor array cables

PRIME Instrument: Field installation


PRIME Instrument: Modular: 16 x 16 (256 electrodes)

HV Supply: 100V (200 V max)

Current: 0.1 - 100mA

Measurement channels: 7-off Gain setting: 1, 10

SP Null: +/- 2.5 VDC Measurement accuracy: ADC +/-5V range: 38uV*

ADC +/- 10V range: 72uV*

Power: 12 VDC (10 W)

Setup & Control: Command file & Scheduling via Ethernet

Access via Web Portal

PRIME - Hardware


SDI Interface: • SDI-12 is a multi-drop interface that can communicate with multi-

parameter sensors • 3-Wire interface: Serial, +12V, GND • Single SDI-Interface supports up to 36 variables • Each SDI-Device has own identity (0-9)(a-z)

Decagon 5TE moisture sensor • 3 Variables: Temp, Moisture, EC

Vaisala weather station • Multiple Variables: Temp, Rainfall, Humidity

PRIME - Hardware


Electrical Resistivity Tomography Imaging – How does it work?


Computer

Data Collection

Data Inversion

Electrical Model

Layer 1Layer 2Layer 3 X XXX X X X X X XX X X X X XXX X

Resistivity Instrument

X X

Elevation(mAOD)

Resistivity ( mW )

160 120 80 40 0

53 70 94 126 168 224 300 400

140135130125120115110105100 Till TillSand and GravelOverlying Sandy TillBromsgrove Sandstone

EstimatedGroundwaterLevel

Data Collection

Electrical Image

Electrical Resistivity Tomography Imaging – How does it work?

Data Inversion


Command Files

& Schedule

Geoelectrical Data

Database Management System &

Inversion Server

Data

Storage

Early

warning

Automatic alarm

Inversion

& web

delivery

Resistivity images

Time

Parameter

conversion

Moisture content images

Time

PRIME Platform: Remote Delivery of Condition Information

Software

Hardware


1 km1 km

Nottingham

Loughborough

Aged Embankment : Great Central Railway, East Leake

GCR Extension: Northern Division - 1899

Barnstone Cutting Fill Northwards

End Tip: Westbury / Blue Anchor Mudstones

(after Dow, 1962)


• Soil moisture

relationships can be used to translate

resistivity images into

moisture content

t24 t25 t26 t27 t28

PRIME – Software (parameter translation)


Cause / Effect: Linking the surface to the subsurface

Predicted positions

GPS measured positions

Time Space

% Change in Gravimetric Moisture Content


PRIME – Time –Lapse Volumetric Monitoring

Contaminant transport


PRIME – Ground Water Rebound

Resistivity monitoring results Automated image analysis


1. Old Dalby Railway Cutting (Network Rail)

2. Llangynidr Canal Embankment (Canal & River Trust)

3. Newbury Road Cutting (Southampton University)

4. Aldbrough Coastal Landslide

5. Charlton Kings Landslide

6. Boxford Water Meadows (CEH)

7. Bristol Water Test Site (Birmingham University)

1 2

3

4

5

6 7

PRIME – Applications across the UK


Future Gazing: Non-Invasive Imaging for Asset Information Delivery

N

N N


East Leake Embankment – Stiffness Model ( MPa ): Aerial drape


East Leake Embankment – Stiffness Model ( MPa ): Fade aerial drape


East Leake Embankment – Stiffness Model ( MPa ): 3D voxelated stiffness > 80 MPa


Liquid limit

Plastic limit

Time Lapse 3D Models: Real-time Asset Condition Indicators


Delivery Platform: Rapid, Remote Control & Information Access

Web Servers

Renewable Power

Permanent or Semi-Permanent

Field Installation

Remote Monitored

Embankments

Database Management

System

Dynamically Configurable

Cuttings

Dams

Remotely: Telecom

Connection

Control / Delivery: On Time

IT Systems-Media

Alerts: Messaging: Threshold exceedance

Asset Management

N


• Database management system: Multi-site management • Parameter translation

• Resistivity to moisture content & groundwater quality • Resistivity to ground motion • Resistivity to subsurface temperature

• Computer vision / pattern recognition • Early warning / alarm thresholds

PRIME – Near Real-Time Geotechnical Images via Geophysical Proxy

Early

warning

Automatic alarm

Inversion

& web

delivery

Resistivity images

Time

Parameter

conversion

Moisture content images

Time

Site Database


• PRIME instrument has been developed – on budget and to specification • Modular, low power (10 W), low cost (~£7k) • Applicable to a wide range of monitoring applications • Multiple installation planned for 2015

• PRIME information delivery progressing well • Working with ITM Monitoring to interface with industry standards • Developing automated image analysis approaches with

Nottingham University • Future development

• New grant applications to develop and demonstrate workflow • Development of high-power PRIME system (ESIOS?)

PRIME - Summary

PRIME: Proactive Infrastructure Monitoring and Evaluation · PRIME . Instrument . Solar . regulator...

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