tunnelling journal feb-mar2015 managing monitoring data

7/18/2019 Tunnelling Journal Feb-Mar2015 Managing Monitoring Data

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COPENHAGEN’S NEW CITYRINGENMETRO line consists of 15.2km of twin

bored tunnels, 17 new stations and fourshafts. Circling the city centre, the line

passes near some of its most historic 18thand 19th century buildings including theMarmorkirken, or marble church. The city

also has a high water table, which must bemanaged for excavation while its level is

maintained underneath existing buildings.

Contractor Copenhagen Metro Team(CMT), a joint venture of Salini Impregilo,Tecnimont Civil Constuction and Seli, must

keep a close eye on many differentelements: movements of ground and

buildings, loads on struts, deflections ofretaining walls, data from fourTBMs, stress and strain in the

tunnel lining segments, waterlevels and water flows, noise and

vibration.“Due to the size of the project

and the technical requirements,we decided we had to go to

someone who had the know-how to do automated

measurements and a databasewhich met most of thespecifications, and could be

easily extended to add theproject –specific requirements,”

says CMT monitoring managerAntonis Charalambides.

CMT chose Geodata’s Kronosdata management software, a

package which collects andpresents data from several

sources and subcontractors. ‘Off-the-shelf’ solutions such asKronos, or Soldata’s Geoscope

can be suited to large projects orprogrammes with numerous data

sources to manage and compare.

For other projects, bespoke systems offer amore reliable and cost-effective solution for

those firms with the right capabilities.A newly emerging tool which promises

some exciting applications in several fields

of civil engineering, is analytics. Arup,Atkins and QuantumBlack have developed

the AIM (Adaptive Instrumentation andMonitoring) application that integrates

analytics to interpret monitoring data.

Analytics have been used in otherindustries such as Formula 1 and aredesigned to work with huge and fast flows

of data. Analytics for tunnelling applicationscan help spot patterns and trends andoptimise monitoring regimes.

Why are you monitoring?There’s a question which seems to be

missing from some monitoring regimes:why? Designers look at what’s been usedpreviously, third parties are looking for as

much monitoring as possible on theirassets, contractors are looking for the

cheapest solution and specialist monitoringcontractors just want to make sure that

data keeps coming, to meet their

contractual obligations.“You can end up with monitoringsystems that are over-the-top,” says Peter

Wright, regional practice manager (tunnelsEurope) at CH2M Hill who is working onthe monitoring strategy for HS2. Over-

18 TUNNELLING JOURNAL

MONITORING

Managingmonitoring data

Figure 1: The basics of Sample Analytics

With data flowing from all directions and multiple sources, how can

clients, contractors and designers ensure they are seeing what they

need to see? Kristina Smith finds out about a number of different

solutions to managing and presenting data.



MONITORING

specification doesn’t just mean that youhave more information to handle, it can

mean that monitoring is less effective thanit could have been had a more modest and

appropriate solution been chosen.“It’s about asking the right questions,”

says Wright. “Is it safety critical? What

activity are you carrying out? If you aredemolishing a building over a tunnel for

instance, manual monitoring of the tunnel

or infrequent automatic monitoring issufficient. If a TBM is passing under anexisting asset, you may need real time

monitoring.”“Some clients take a blanket approach

and say ‘everything needs monitoring’,”says Stewart Harrison, chief surveyor forBam Ferrovial Kier (BFK) on the C300/C410

Western tunnels and stations contracts forCrossrail. Specifications can be vague, he

says, simply stating that a structure shouldbe monitored and some contractors don’t

have an understanding of what particularmovement or mechanism monitoring

should be watching for.Third-party asset owners can also demand

unnecessarily large quantities of monitoringdata. “You need to talk to third party assetowners up front and get economic and

efficient monitoring agreed if you want toavoid systems that are over-specified,” says

Wright. “The key is to actually getmonitoring experts in place at the design

stage. That’s what I am proposing for HS2.We need people who can write guidelines

for monitoring equipment up front.”One knock-on effect from huge amounts

of data is problems with the quality of thedata produced. False alarms are a commonproblem. “With these flows of data

approaching all the time, you do get badresults which mean that there are

disturbances to the systems so that errors

can happen,” says Klaus Rabensteiner, CEOof Geodata.

“If the values are not verified, we have alot of false alerts so we need algorithms tocheck the validity of the data, to sort out

the false alarms,” says Rabensteiner. Theway various packages do this varies widely

from provider to provider, he adds.Stewart thinks that problems with false

alarms are due to a much more

fundamental issue. Rather than algorithmsto remove rogue results, monitoring systemsshould be properly designed so that the

rogue results don’t occur. The waymonitoring contracts are procured does notnecessarily encourage this approach:

“Subcontractors are concerned withdelivering data, because that is how their

contracts measure them,” he says. “Theredoesn’t seem to be anything in any contract

that says the data has to be any good.”An industry-led group in the International

Tunnelling and Underground SpaceAssociation (ITA) is currently working to set

minimum standards on what informationand monitoring management systemsshould look like for various project types.

Led by Rabensteiner, the group isdeveloping guidelines on what it calls ‘plug

and play’ data management systems (seebox).

“Contractors are confronted with anoverload of data,” says Rabensteiner. “They

need that data to be easy to handle andthey need a clear concept of what to do

with all the data, how to collect it fromdifferent sources, how to combine and

connect the data in order to extract the realinformation.”The guidance should help designers

define monitoring regimes, saysRabensteiner: “Monitoring is part of the

feedback process. It has to be seen in a

bigger context. Monitoring gives feedbackto the design and allows adjustments forthe next steps.”

Kronos in CopenhagenThough European metro specifications havebeen requiring monitoring databases for

over ten years, the Cityringen project calledfor something Charalambides has not seen

before: multiple subcontractors feeding

information into the one database.“We had never worked this way before,”he says. “On other projects, there was onepartner sending TBM data and the

monitoring department collecting its owndata; only two sources. On this project we

have a large number of subcontractors andsources which are uploading different types

of data and information.”In addition to monitoring and TBM data,

the database receives data from thegroundwater management department, the

environmental department additional waterlevel measurements from two external

sources, construction progress from sites,borehole profiles from two drillingcompanies and evaluation data from the

geotechnical designer.This is a trend which Charalambides

believes is set to continue. Cityringen hasbrought some useful lessons for CMT and

specialist monitoring subcontractor SMT.“It did raise an issue of quality of

measurements, who checks, who corrects,who has responsibility?” saysCharalambides. “In the future we will put

more weight on the description of the

quality requirements for uploading data,cleaning, correcting measurements, anddefine a clear grid of responsibilities.”

Though false alarms are commonplacewhere large amounts of automated data are

involved, the frequency was a problem for

TUNNELLING JOURNAL 19

Defining A Plug-And-Play SystemITAtech was set up in 2011 in a bid to keep the industry up-to-date with

advances in materials, practice and technology and encourage speedier

take-up of ‘new’ products and systems. Unlike the International Tunnelling

and Underground Space Association’s (ITA’s) more academic committees, theITAtech Activity Groups (AGs) are made up of manufacturers, designers and

contractors with a remit to put guidance and standards together as swiftly

as possible in order to encourage adoption of newer technologies.

The Monitoring AG, headed up by Felix Amberg, president and owner of

Amberg Technologies, has already published one document ‘Guidelines on

Monitoring Frequencies in Urban Tunnelling’ in 2014, which sets out how

often hydro-geotechnical and structural parameters should be measured.

Now a Monitoring Sub-AG, headed up by Klaus Rabensteiner CEO of

Geodata, is working to produce guidance on information and

communication systems. The guidance, ‘Effective Data Management in

Tunnelling’, will define what a ‘plug and play’ system for all data on site

should look like.

The overarching aim of the guidance is to demonstrate the benefits that

a well thought-out communication and information system can bring to a

project in terms of safety, risk management and cost. It will tackle issues

such as how to write good specifications, how to choose between available

systems and make recommendations on exchange standards for data.

The paper aims to communicate what data management systems can dothrough a series of case studies. “We want to share experiences from a lot

of different projects, and from various viewpoints,” explains Rabensteiner.

“We have produced the paper in draft but it does not fully achieve this aim

in an appropriate way yet.”

Ideally, Rabensteiner would like case studies to illustrate success stories

and lessons learned, although finding people who are willing to reveal all

about their projects is tricky. Another challenge for Rabensteiner is finding

companies and individuals who are willing to invest time in developing the

guidelines.

The following firms are involved in the sub-AG: ITMsoil, Soldata,

Geodata, Amberg Technologies, Babendererde Engineers, Astrium Services,

Herrenknecht, VMT and Seli. ITAtech would welcome other companies,

particularly consultants, to join the group. Those interested should contact

[email protected]



MONITORING


Cityringen initially. “It happened too often at

first which is why we added a first levelfunction which filtered out measurements

which we are sure to be incorrect. This doesallow for a number of measurements everyday which are false and these are captured

on a second level, where they are manuallyconfirmed or deactivated.”

The first-level data handling process,developed by CMT and SMT, sees automatic

checking using algorithms to recognise andfilter out the majority of incorrect

measurements, followed by manualverification of measurements by SMT, and

finally interpretation of the measurements byCMT.

“The automatic checking was something

we recognised as very essential to the

operation of the system,” says

Charalambides.” It was not described in thetechnical specifications but you either need

lots of people continuously looking atcomputers and finding out where the wrongmeasurements are or you need the system

itself to be able to recognise wheremeasurements are certainly wrong and clean

itself.“One of the challenges we had in

developing it was how to regulate it toremove most of the incorrect measurements,

while reducing the risk of removingmeasurements that could be correct andwould generate real alarms.”

The client was kept informed about thesystem’s architecture and how the cleaning

algorithms would work. “We developed it

with common knowledge and acceptance of

all the implicated parties,” saysCharalambides. “One of the fundamentalthings is that we don’t delete anything. Users

can select to see the ‘cleaned’ or all themeasurements.”

Kronos’ alarming system has providedCMT with early warnings several times, says

Charalambides. “On at least three occasionswe were able to mitigate risks when we

found out that loads on struts weredeveloping faster than expected,” he says.

“In one case we moved the position of amobile crane, in the second we moved astockpile of excavated materials and in the

third instance we placed an additional strutin order to maintain the excavation safe.

After those remedial actions, excavation

Figures 2 and 3:The upgrade of

London BridgeStation involvesdemolishingmasonry arches

which are currently

supporting thetracks to make wayfor a huge newconcourse. Arches

either side arebeing retained bybuttresses andmonitored closely

during the works.



MONITORING

could continue. The early warnings allow usto mitigate problems before they become

significant.”Charalambides makes the point that all

data management systems must be bespoketo some degree. “I don’t think a plug-and-play system that covers everything exists,” he

says. “There are always local requirementsand needs. You need a good basic system

that can be easily adapted.”For example Denmark also has its own

format for recording and exchanginggeotechnical information, GeoGIS. Kronos

was set up to be compatible to AGS, awidely used format for recording and

exchanging geotechnical information. So aninterface to make Kronos compatible with

data in the GeoGIS format was required to

be included.Monitoring regimes will also vary betweenregions. On Cityringen the specifications

suggested moderate-to-high frequencymanual measurement in stations and some

parts of the tunnels, but this would not havebeen cost-effective. Says Charalambides:

“When we started planning how the

entire monitoring system would be set up,we realised that we would need an extensive

team to perform, verify and upload therequired measurements. In Northern Europe

this is not really an option – the cost ofpersonnel does not allow it. The only cost-

effective way was to introduce automation. ”In other parts of the world, manual

measurements could be a better solution.

Geoscope 7 at London BridgeThe overground station at London Bridge iscurrently undergoing a circa £750M

upgrade, courtesy of Costain, which willincrease the number of trains it can

accommodate from a maximum of 70 to 88an hour. At the heart of the project is a

massive new concourse which will allowaccess via escalators and lifts up to all the

station’s 15 platforms. At the moment, theplatforms are in two groups, each with itsown access.

London Bridge’s tracks are built on top of150-year old masonry arches. In order to

create the new underground space for the

concourse, the arches and tracks above themmust be demolished and a new structure and

tracks constructed. This is happening in ninephases to minimise disruption to the station.

Having won monitoring contracts for the

gigantic glass Shard building right next toLondon Bridge station, and on the Shard’s

baby brother The Place, Soldata completed ahat trick of wins when Costain appointed it

to work on the station redevelopment in2011. It is using its Geoscope 7 software,

launched commercially last year after fiveyears of development, to marshal and

compare multiple sources of data.Geoscope 7 is also being used on

Tottenham Court Road underground station

redevelopment in London, on the AlaskanWay viaduct in Seattle, and on metro projects

in Rennes, France, Riyadh, and Doha.Unlike its predecessors, Geoscope 7 canhandle much more than monitoring data,

says Soldata marketing manager AidanLaimbeer. “It’s a risk management tool whichenables you to integrate any database in a

timely manner and present the data in a waythat’s open, accessible and understandable.

The amount of databases you can have isphenomenal.”

Information related to compensationgrouting, TBM progress and weather

conditions, as well as monitoring data couldall be presented. “In some cases we are

using it as an observational method tool,”says Soldata technical manager MatthieuBourdon. “We can link into the pre-

excavation grouting contractor’s databasesand compare pressure and volume with

ground movement.”“The user interface is more graphical and

more intuitive than the previous version andit works with tablets,” says Alex Lawson,

duty operation engineer for Costain atLondon Bridge. “You can have any

combination of data you want very easily. Sofor example, you can overlay track settlement

with arch settlement to see if they arerelated.”Since the contract began, Costain has

chosen to direct more and more informationthrough Geoscope 7. “If somebody’s data is

good, but we don’t like their interface, we

put it on this,” says Lawson.

The instrumentation at London Bridgeincludes over 30 automatic total stations

(ATSs), electrolevels underneath the masonryarches, tilt meters on London Underground

escalators, inclinometers inside piles forretaining walls, strain gauges and

piezometers. There was also vibrationmonitoring earlier in the programme.

“The project is very dynamic,” says Soldataproject manager Nathalia Arevalo. “Because

they are demolishing two tracks at a time,we have to get in there and install theinstruments before the next phase of the

works starts.”In addition to Soldata and Costain,

geotechical engineers, surveyors, specialistcontractors, London Underground and

Network Rail can all see the informationrelevant to them through Geoscope 7. Each

has their own user rights for accessing the

database.With a project as complex as London

Bridge, there have been several instanceswhere ground and building movements have

required further investigation, such as whenpiling for a buttress wall to support

remaining arches is underway. At thesetimes, the ability to quickly compare and

overlay different information is invaluable,says Lawson.

“One of the really useful features ofGeoscope 7 is the layer management: you

can compare ten different sources of data,

and if you see something that you want toalert other people to, you can save that view

and send it to the relevant people,” saysLawson. “Overall, it’s so much more efficient

which means you have more time to spendon other tasks.”

Tight and bespoke at PaddingtonFor the excavation of the TBM tunnels underPaddington Station box for Crossrail, BFK

elected to use an in-house designedmonitoring system. “We didn’t want to domonitoring just for monitoring’s sake,” says

Harrison. “The system was scientifically

designed to meet our needs as thecontractor.”

One of the factors behind BFK’s decision to

design its own monitoring system was that ithad experienced data quality issues with

monitoring subcontractors. Harrison feelsstrongly that algorithms to remove rogue data

are not what’s needed here; a properlydesigned system should avoid erroneousreadings, and use advanced survey concepts

to take out the noise or undulations inmeasurements.

The challenge at Paddington was that

programme constraints meant thatCostain/Skanska JV had to construct the 24m-deep station box as the tunnels beneath –

eventually to be broken out – were still servingthe TBMs. Movements in the tunnels had to

be predicted before the contractor could


“This method stabilises the results,reducing system noise and iscalibrated specifically to follow theexpected slow trendingmovements during and after theperiod of excavation,”



MONITORING


decide to take this approach, and themonitoring system had to check the actual

movements to ensure the stability of thetunnels and the safety of the operation.

The in-tunnel monitoring system wasmodelled virtually and checked using Star*net

software, which carries out least-squaresadjustments of survey networks. Least squares

adjustment is a mathematical procedurewhich looks at multiple measurements in a

network and finds the best-fit solution and it’ssomething Harrison has been applying since

2007. The monitoring network consisted ofthree automated total stations in each tunnel,

with prisms every five to six rings at sevenpositions round each ring. The virtual model

allowed BFK to check lines of site andinstrument positions among the ventilation

bagging, tracks, walkway and

other services to minimise theamount adjustment required once

the kit was installed on site.Harrison describes the system as

an ‘organic network’. By this hemeans that the network fixes

points outside the zone ofinfluence of the works and

partially fixes points within thezone of influence to the lastknown value, allowing those

points to be used as a control.“This method stabilises the

results, reducing system noise and

is calibrated specifically to followthe expected slow trendingmovements during and after the

period of excavation,” saysHarrison.

The results obtained frommonitoring during the excavationcorrelated closely with those

predicted during the design phase.And no filtering or smoothing of

the data was required, saysHarrison.

This was an efficient solution for

the excavation of the PaddingtonStation box, made possible by thefact it has in-house expertise.

However, contractors may nothave the resource to build bespokesystems, especially where large

projects and programmes requiremultiple data sources to be

managed at once.

Formula 1 comes to FarringdonArup and Atkins are employing a

technique honed in Formula 1 tohelp their engineers make sense of

monitoring information. Theconsultants have been workingwith analytics specialist Quantum

Black to develop something theycall Adaptive Instrumentation and

Monitoring (AIM).Having carried out a pilot study,

Arup proposed the use of AIM onCrossrail’s Farringdon and

Whitechapel Stations. Other metrodevelopers including MTR in Hong

Kong and LTA in Singapore arealso reported to be interested in

what AIM can do.“With many monitoringcontractors’ software packages,

the graphical interpretation is clearbut they don’t introduce

construction progress and trying to

Figure 4: Sample Daily Report Sheet from Paddington (Movement Time Plotsvs Construction Activity)

Figure 5: Predicted vs Actual Tunnel Movement at Paddington



MONITORING


correlate it with the monitoring data isdifficult,” says Arup associate director MikeDevriendt. “Contractors were presenting

monitoring information to us in a ratherdisorganised way, and construction data was

not being represented alongside it. It was

taking our engineers as much time piecingtogether what construction event had causedthe movement as the time spent reviewing

the data and interpreting.”AIM presents ground and structural

monitoring results in a clear graphical waytogether with construction progress. But theclever bit is the analytics: looking for patterns

of data which can give early warnings or helpoptimise monitoring systems.

“If you have racing cars going round aFormula 1 circuit, you are trying to look at

data channels and spot problems with theengine or the tyre pressure, looking for trends

in the data,” says Devriendt. “Similarly withreviewing tunnelling-induced ground

movements, you need to spot trends whichare concerning and discern them fromanomalies in the data.”

The analytics in AIM can do three things:spot anomalies in the data and distinguish

between errors and concerning trends;continuously update mathematical models to

forecast an end result; and look at theinterdependence of points with respect to

space and time, and suggest where there maybe redundancy in the system.

“It has the potential to make monitoringinstrumentation design more efficient,” saysDevriendt.

For contractors, this could lead to morecost-effective procurement of monitoring

services. “For clients tendering monitoring

works, rather than opting for a lump sum

contract it may make sense to goremeasureable,” says Devriendt. ”Install a

robust amount of instrumentation then dialup or down the frequency of measurement.”

Setting the frequency would require

engineering judgement, considering whatconstruction activity was next and whatredundancy the analytics had identified.

”This could be one way to make savings,although such an approach needs to beagreed with third-party asset owners,” says

Devriendt. ”However, in speaking with manyasset owners in recent years, there is a

willingness to review these novel approachesif they offer greater visibility of data”

Interpreting monitoring and constructionprogress data is just one of numerous

potential applications for analytics in civilengineering. Others include processing data

gathered from the measurement trains whichsurvey railways or baggage handling systems.

No more middle man?What all these solutions have in common is

the ability to connect client, engineer andcontractor to the data more directly and more

effectively. The end result should be a moredynamic use of monitoring data to help

inform immediate and future decisions aboutdesign and sequencing.

Both BFK’s in-house approach and ArupAtkins QuantumBlack’s analytics solution

demonstrate contractors and designersattempting to take more ownership of howtheir monitoring data is served up. “Our

software has been designed by engineersinterpreting the data rather than monitoring

contractors, who are contracted to provide

the data,” says Devriendt.

The need to give the user more control issomething Soldata acknowledges too.

Bourdon expects that some organisations willchoose to buy Geoscope 7 without also

procuring Soldata’s services.

“It’s the first time that software gives thekeys to the client,” says Bourdon. “It’s a newstrategy. Until now, monitoring companieswanted to control the data. It was compulsory

to use a specialist contractor to manage thedata. Now you can employ people internally,

remanage the costs.”Mehdi Alhaddad, a PhD student at the

Cambridge Centre for Smart Infrastructure,reminds us of another strong force for change

in this area: generational differences.“Updating our current 'data interaction' tools

is a crucial task that our industry must takevery seriously, especially if we want to appeal

to the new generation of civil engineers whoare often disappointed when they comeacross our current tools,” says Alhaddad. For

him, tools such as AIM present data “in aform that is closer to what a modern brain is

trained to digest.”Those from Alhaddad’s Millennial

generation, aged between 20 and 34, havegrown up with mobile, smart technology and

– unlike some of their older counterparts –may not be able to work with columns ofdata listed in a spreadsheet. Of course, these

generational differences do not apply to every

individual but they do point to trends.It will be interesting to see what sort oftools the brains of Generation Z, those aged

20 and younger, will work best with. Expectsome exciting new developments in the not-

too-distant future.

Figure 6: Adaptive Instrumentation and Monitoring (AIM) application



MONITORING

OVER THE LAST TWENTY YEARS Asia has

been home to some of the world’s largest andmost complex tunnelling projects. Many of

these have been delivered within challengingground conditions and ultra-competitive

markets. Whilst there have been commercial

and technical failures which have dominatedthe press there have also been many notable

successes. The region’s response to therequirements of the Joint Code of Practice

2004 has been laudable and in all Asiancountries formal risk management procedures

have been driven through by clients andconsultants and embraced by contractors.

Our ability to measure what we do is greaternow than ever before and as a result there has

been an explosion in the amount ofinformation which needs assimilating andcommunicating. This has raised a number of

challenges. The need to process and review all

this information puts a large strain onmanpower resources and as a result Engineersand geologists have become slaves to word

processors and spreadsheets. More time isoften spent handling information rather than

analysing it. Typically engineers are resourcefuland many develop their own systems to

manage this workload but this plethora ofpersonal systems limits the extent to whichdata can be communicated and collaborated.

Often projects and their data arecompartmentalised and run by different teams

each with differing focus and agenda. How

often have we been told “talk to Production”or “talk to Geotech” in response to a requestfor information? The goal must be to enable

Production to answer a geotech questionbecause they are themselves informed on

geotechnical issues.Maxwell Geosystems have been at the

forefront of a quiet revolution in Asia which

started in Hong Kong in 1997 with theStrategic Sewage Disposal Scheme. This was

the first project to implement a project wideinformation system to collect as much

structured data as possible about all aspects ofthe construction process. The initiative was

born out of client and engineer frustration atthe inconsistency in reporting across contract

teams on the same large project. The widelypublicised contractual difficulties focussedattention on data and how it would be

managed given that future arbitration wasinevitable. This buy in by the project top brass

gave the initiative impetus and by 1998 thesystem was managing all data on the three

replacement contracts and producingstandardised reports to government. This was

not without some difficulty. In 1997 theinternet was not so reliable and the system

had to rely on daily merging of multiple sitesdata into the central system. Whilst clunky thiswas effective and by the end of the project

every 15 minutes of time, every hole drilled,support installed and geology logged had

been loaded into one system which

comfortably sat on one CD. Accompanied by a

database of over twenty thousand fullyindexed photographs readily accessible inpaper and digital form the system was a key

component in the client’s successful arbitrationcase.

Overcoming inertiaSystems such as these always fight againstinertia to be established. We are told that data

is power and it is true that individuals seeownership of data as important and a way of

achieving competitive advantage. We all striveto have “better data” than the next guy.

However, once in place all but the moststubborn become advocates particularly if theycan get to their information and the

information of others quickly and easily andsafe in the knowledge that it has been audited

for quality and correctness.

The usefulness of the systems become most

apparent during the planning for the highlysensitive stage 2 around Hong Kong Island.The detailed data on production, in particular

the effect on poor ground and water inflowcombined with statistics for drilling and

grouting and the observed sensitivity ofoverlying deposits were instrumental in the

delivery of the project through feasibility todetailed design and construction. With greater

certainty on required quantities and risks theengineer was able to go to tender with a farmore equitable contract and a much lower risk

solution involving drill and blast. The tunnels

were completed in 2014 with no repeat of thecontractual or settlement issues which plaguedphase 1.

Formalised dataThe benefits of formalised data management


Figure 1: An early TDMS implementation on Hong Kong West Drainage Tunnel

Dr Angus Maxwell and Dr Andrew Ridley of the

GEOMAX Partnership describe how automated

risk management has been achieved using

integrated systems on some of Asia’s largest

tunnel infrastructure projects.

MISSIONPOSSIBLE



MONITORING


have been embraced by the GeotechnicalEngineering Office and the requirements for

Tunnel Data Management Systems have nowbeen promulgated gradually through allgovernment departments. Initially the systems

were driven through conventional Engineer’sdesign contracts using standard ICE terms.

They were placed under the consultant’s

contract with the intention they be deliveredby the resident site staff and populated by theinspectors and engineers. Later this was

passed down to the main contractor’scontract. This led to some difficulty gaining

buy in since the systems were initially seen as anoose by which the Contractor could hangthemselves. As a result only the minimum

contractually obligated data was entered andstrictly to satisfy the contract rather than as an

integral part of the contractors daily methods.Over the past eight years of implementation

contractors have come to realise that thesesystems can be used to their benefit whilst also

satisfying the contractor’s requirements. Thesystems recently installed on the Klang Valley

Metro in Kuala Lumpur have replaced manualmethods of producing AAA response reportswith live reports generated on demand from a

secure blogging facility. Each alarm starts athread and the organised responses to the

thread follow the agreed procedure. Thecontractor saves time, the communication and

reaction time is quicker, engineers spend moretime on the solutions than on the reports and

we don’t cut down trees.Since the much publicised Nicol Highway

failure in 2004 the Land Transport Authority inSingapore have removed all responsibility forprotective instrumentation and monitoring

from the main contractor and put it under thegovernment body. Whilst this ensured

impartiality, the MTRC in Hong Kong adopted

a different approach driven by the desire toleave monitoring with the party best able tointerpret and respond to it. The MTRC put in

place a party whose responsibility it was toverify the data by independent measurement

and to publish the data to all parties so that allinformation could be seen. This was the

Independent Monitoring Consultant.

The Regional Express Line (XRL) monitoredover 30000 instruments along its 25km lengthand the IMC check measured approximately

15% of the contractor’s values and loaded alldata IMC and main contractor into a centralisedatabase. The physical checks were particularly

effective in raising the confidence in the dataquality and delivering information quickly to

the contractor but were only truly effective in adesign sense when parties were encouraged

to regularly provide groundinvestigation, design prediction and

construction progress data so thatcause, effect and expectation could

be monitored. This was particularlyapparent for the 400m x 250m x30m deep station excavation in

West Kowloon. Whilst successful,the motivation for contractors to

engage was uncertain still seeingthis as a client’s risk reduction tool

and an effective one at that with theIMC contract being a contributory

factor to a reduction in negotiatedproject insurance.

While all this was unfoldingAustralia were promoting the use of

Alliance forms of contracting onProjects such as the Inner NorthernBusway, Gateway Motorway and

Airport Link in Brisbane and theBallina Bypass in New South Wales

and the systems blossomed in this

hats off approach. Early systems weredelivered with engagement from designers toenable them to get feedback on their designs

in real time. The designers designed what theywanted the systems to do and the system

consultant made it happen. On the rapidlychanging sites the system became the focus

for the daily permit to tunnel risk assessments.Such collaborative risk management was

the key motivator behind Singapore Power’sdecision to implement their IDMS system in

2013. With two projects and 16 simultaneousTBM drives under very sensitive infrastructurethis is one of the largest tunnelling projects in

the world. Previous cable tunnel projectswhich had encountered significant settlements

during the construction stage triggered theneed for comprehensive instrumentation data

management systems. It was hoped thiswould allow all parties (client, consultants &

contractors) to access the basis of design data,

Figure 2: West Kowloon Station linking progress monitoring design andconstruction data

Figure 3: Keeping it simple.Singapore Power Cable Tunnels –16 consecutive TBM drives

monitored in one platform

Figure 4: No CAD bottleneck. Deep shafts andtunnel connections are best explained with

real time BIM programmatic constructions



MONITORING

real-time and manual monitoring data as wellas the construction activities carried out at site

through a common platform that provideinteractive functions to generate graphical

plots linking the monitoring data and theconstruction activities. Based on the cause and

effect information, the system will allow the

project team to predict, forecast and use thesystem as the risk management tool for look-

ahead construction activities.In common with Singapore government

projects the instrumentation contracts weredirectly let under the owner and supervised by

the QPS. Centralised collection of these resultsand site observations from the QPS teams

would be straight forward but the collection oftunnelling information would need the

cooperation of the contractors.The Client negotiated with all six contractors

on the project to request them to contribute to

a centralised system for the management of

risk as part of the partnering process. The costof the system was equally shared by all sevenparties including client and contractors. Whilst

still seen by the contractors as an owner’sinitiative, the requirement to have a financial

stake motivated contractors to use the systemfor their benefit.

The system scope and delivery was managedby a steering committee with representativesfrom all the financial contributors. In addition

to providing the system the IDMS consultantalso provided staff to maintain the data and

provide a line of communication for users. The

team was managed by an experiencedinstrumentation and geotechnical engineer.The critical key to success was the presence of

director level drivers within all the teams whodemanded the use of the system across the

projects and weaned the staff away from theirspreadsheet and word zones of comfort into anew way of operating using open booked data

and effective media sharing andcommunication methods.

The systems now enable all the engineers toaccess any data and draw any map, section

graph or table for instruments TBM orproduction parameters ground investigation

and other digitised data sources such ashazards. The system embeds contractors

design predictions as they change through aproject enabling all parties to establish theexpectations of the works and identify early

areas of concern and trends. All of theseanalyses can be designed into custom canvases

where each user can tell their own story.

Allowing engineeringSystems will never replace engineers but they

will increase the proportion of time engineersspend doing engineering. They also enable

relationships to be observed which wouldotherwise be missed and this is the realbenefit. Above all engineers can now do in

real time the type of analysis that was normallyreserved for several weeks of forensic

investigation after a problem had occurred.

Figure 5 a to c. Engineers need the ability to undertake the kind of analysisnormally reserved for forensic investigations of failure….before the failure.

tunnelling journal feb-mar2015 managing monitoring data

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