3/16/2018 TBM excavation begins for Kuala Lumpur Line 2

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15 Mar 2018

Prime Minister Najib Razak of Malaysia (inset right) joined TransportMinister Datuk Seri Liow Tiong Lai (insert left) to launch the first of

12 TBMs to work on the KVMRT Line 2 underground route

TBM excavation begins for Kuala Lumpur Line 2Shani Wallis, TunnelTalk

Building on the legacy of the Line 1 experience, the first of eight refurbished VDM (variable density TBMs) previouslyused on Line 1 was launched in early March to begin excavation of 13.5km of twin tube running tunnel for the KualaLumpur Klang Valley metro system in Malaysia. Excavation of the Bandar Malaysia North underground station boxprovides the working access and launch site for the first of 12 TBMs to link the 11 stations on the 13.5km undergroundsection of the city’s second 52.2km long mass transit route.

Marking the official milestone, Prime Ministerof Malaysia Datuk Seri Najib Razak pressedthe button to launch the refurbishedHerrenknecht VDM (variable density) TBM onits 1.4km drive towards the Chan Sow Linunderground station where it will be re-launched to complete the 1.275km drive tothe Line 1 interchange Tun Razak Exchangeunderground station. Four TBMs arriving fromboth directions at Tun Razak Exchange stationwill be dismantled underground and removedeither through Chan Sow Lin or ConlayStations. The refurbished machine will bejoined by other seven refurbished Line 1 TBMs– five refurbished DVMs and two refurbishedEPBMs - and an additional four newHerrenknecht VDMs to complete the total27km of segmentally lined underground routebetween the north and south transition portalsin 16 separate drives (Fig 1). All twelve Herrenknecht TBMs are planned to be in operation by the end of 2018 with fourof the machines relaunching in early 2019 for the final two, twin tube reaches (Table 1).

Continuing its association with the metro system, the same MMC-Gamuda construction JV that completed theunderground section of the central underground section of Line, was awarded the MR15.47 billion ringgit (about US$4billion) underground central section of Line 2 by MRT Corp, the Mass Rapid Transit Corporation, of the MalaysianGovernment, in March 2016. Retaining the eight Herrenkencht TBMs used on Line 1, gave the JV a competitiveadvantage over its rivals for the Line 2 contract. Refurbishment of the eight machines is said to have saved the MMC-Gamuda up to RM400 million or about 15% of what it would have cost to purchase new machines.

Refurbishment for reuseIn addition to being well maintained during their drives and with detailed records kept throughout their operation tomonitor maintenance and provide useful information for the refurbishment process, preservation measures were appliedto the Line 1 TBMs, before they were placed in long term storage ahead of refurbishment for use on Line 2. MMC-Gamuda then worked with Herrenkencht to complete a comprehensive rebuild of the machines for their Line 2 reuse.

In explaining the refurbishment completed, Gus Klados, Director, Tunnels for the JV for Line 2 and for the previous Line1 project, emphasized the risk taken by MMC Gamuda “and the trust we had in our judgement, that these VDMmachines - that existed only on the drawing board when we ordered six of them from Herrenknecht in 2012 - wouldwork as hoped for in reality”. Operation of the machines in the karstic limestone geological conditions and the EPB claydeposits under the city of Kuala Lumpur certainly proved their worth with all of them completing their drives with nomajor technical difficulties or issues and with the concept now being applied on tunneling projects elsewhere in theworld.

The refurbishment process included stripping, cleaning, refurbishment and replacement of worn parts, modification andupgrade of other components and progressed to factory acceptance tests. Each cutterhead was assessed separately andfully repaired as necessary. Two of the cutterheads that had suffered particular wear around the periphery were rebuiltwith harder wearing Vautid blocks.

3/16/2018 TBM excavation begins for Kuala Lumpur Line 2

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Fig 1. Line 2 in red, is 52.2km long with the central13.5km and 11 of the 35 stations aligned underground

The first TBM launched is the first of eight DVMs usedpreviously on the Line 1 project

Table 1. Proposed schedule for launching two TBMs, one monthapart, at each Tunnelling Unit (TU) working access site withfour TBMs relaunching in 2019 after completing their initialLine 2 drives and dependent on station excavation progress toprovide launch and working accesses

Main bearing assessmentThe main drive sealing, rotary couplings, thrust andarticulation cylinders were pressure tested toconfirm their integrity and the erector bearingswere inspected and found reusable except for onone machine which was replaced. The screwconveyors were checked for wear and rebuilt andprotected with hard facing as necessary and allsafety, hydraulic, electric, lubrication, grouting, andsoil conditioning systems were checked andrepaired as required.

The design life (L10) of the main bearing in each ofthe machines was calculated by Herrenknecht andbearing supplier SKF and the residual life of all wasfound to be more than sufficient to cater for theirLine 2 applications. The remaining L10 life of all thebearings was found to be in excess of 300% of theirprojected operating hours for the Line 2 drives.

The bearing in one of the TBMs was replaced after it completed more than 4km on Line 1, launching from Cochranestation, boring through the Tun Razak Exchange and Bukit Bintang underground stations and continuing after beingpulled through Merdeka Station to a final break through into Pasar Seni Station. The VDM was the first launched on Line1 in June 2013 and the last to breakthrough in April 2015 and after working in the VDM mode through limestone at thestart and in EPBM mode through the complex Kenny Hill Formation of multiple metamorphic deposits of clay, silt, sand,phillite and a section of 290MPa quartz on the alignment. On inspection, its main bearing showed signed of some soilcontamination damage and was replaced with a new one.

“The life of the bearings was a subject of scrutinyby the client,” explained Klados, “and the analytictable of each was submitted with our tender forthe contract.”

Rotary crusher sizerThe one item of modification was the operation ofthe rotary crusher and sizer component on theslurry circuit of the VDM machines (Fig 2). Thesecrushers/sizer units sit above the slurrifier boxand had proven to be a bottleneck in poor blockyground conditions during Line 1 operations. PaulTrevisin, Senior Project Manager for MMC-Gamuda, explained that as part of itsmodification, “the configuration of the crusher

3/16/2018 TBM excavation begins for Kuala Lumpur Line 2

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Table 1. Proposed schedule for launching two TBMs, one monthapart, at each Tunnelling Unit (TU) working access site withfour TBMs relaunching in 2019 after completing their initialLine 2 drives and dependent on station excavation progress toprovide launch and working accesses

The rotary crusher sizer above the slurrifier box in the DVM slurrysystem underwent improvement modification

drums and tools was redesigned to change theangle of inclination of the drums to lie morehorizontally above the slurrifier box and reducethe tendency for stones to fall rapidly to the endof drums. The crusher tools were also changed toroadheader picks for a more aggressive jawaction.”

The modified crushers will allow the VDMs to passthrough those challenging local karst conditionswithout being slowed by the blockages. “The fournew VDMs ordered from Herrenknecht for Line 2were equipped with the modified crushers,”explained Klados.

Other upgrades, described by TBM Manager NgKok Peng, involved modification of the flushingsystems into the EPBM and VDM excavation

chambers. “The two EPBMs had their rotary couplings changed to provide an extra passage to flush the central doublecutter region of the cutterhead to prevent blockages and the central flushing ports into the excavation chamber of theVDMs were redirected to deliver further forward and prevent blockages around the double cutters during high-densityexcavation operation.”

“For two of the new VDMs machines we havehad them fitted with dual manlocks to facilitatefaster cutterhead interventions for toolchanges,” said Klados. “This is expected to benecessary for working through the highlyabrasive granite on the northern drivesbetween Titiwangsa Sation and the northtransition portal.”

With the first of the 12 TBMs now underwayand its twin drive machine preparing for launchwithin the coming weeks, the concentratedeffort to complete the underground section ofthe new Line 2 for the underground system isunderway and towards a line opening deadlinein 2022.

Circle Line procurementAs TBM tunnelling gets underway on the underground central section of the new KVMRT Line 2, news is reported thattwo consortia are shortlisted for construction of the third MRT3 Circle Line. Designed now as an all-underground route,the two consortia are the MMC-Gamuda JV and joined for MRT3 by George Kent company, and a consortium lead by theChina Communications Construction Company (CCCC) which presented strong competition for the Line 2 undergroundconstruction contract.

The Malaysian Government approved construction of the MRT3 Circle Line in October 2017 and conducted initialindustry briefings with four turnkey project contractors in November. The other two consortia are reported as theSapura Group-TIEC-Samsung Corp consortium and the Pacific Construction-Mudajaya-JEC group. As part of theirproposals, the MMC-Gamuda-GK and CCCC consortia will also be required to offer a financing package to contribute tofunding the estimated RM 45 billion (US$11.5 billion) MRT3 project. The Circle Line is last of the three-line metrodevelopment proposed to the Government by MMC-Gamuda in 2010. Following this, the JV was engaged as the ProjectDelivery Partner to realize Line 1 of the masterplan.

ReferencesKVMRT to repeat Line 1 success for Line 2 – TunnelTalk, April 2016

Final breakthrough ends KVMRT TBM tunnelling – TunnelTalk, April 2015

Kuala Lumpur Line 1 starts full operation – TunnelTalk, July 2017

High honour for metro director in Malaysia – TunnelTalk, September 2017

Honours for an international tunneller – TunnelTalk, February 2017