Shani Wallis, TunnelTalk
- An EPBM supplied by CRTE from China has scored the first breakthrough of many to be recorded as work progresses on the Klang Valley MRT project in Kuala Lumpur, Malaysia. With a total 10 TBMs procured to excavate the twin running tunnels of the central 9.5km of the 51km long first metro line for Malaysia's capital city, breakthroughs will be registered at seven underground station boxes, intermediate shafts and open-cut crossover sections as peak excavation activity carries on through 2014.
- The second machine has broken through for completion of the 6.67m diameter parallel tube of the 1.4km long Semantan North-Sentral Station section of the Klang Valley MRT project in Kuala Lumpur.
Celebrating third breakthrough in Kuala Lumpur
- Following breakthrough of the Semantan 1 machine on Christmas Eve (December 24), its sister machine Semantan 2 broke through to complete the parallel tunnel on January 16.
- The news is a boost for Chinese TBM manufacturer CRTE, which supplied two of the 10 machines ordered by MRT Corp's tunnel contractor MMC Gamuda for the 9.5km-long underground section of the new 51km line between Sungai Buloh and Kajang.
- A third machine - one of six new-design Variable Density TBMs supplied by Herrenknecht to tackle the karstic limestone that characterise part of the alignment - achieved breakthrough earlier this month (January).
- The first breakthrough, by one of two 6.67m diameter EPBMs supplied to the project by the China Railway Tunnelling Equipment company (CRTE), was celebrated on 25 December when the machine pushed through into the open cut Sentral Station box job site. The machine had launched at the Semantan North Portal in June 2013 and had made good progress to compete the 1.4km long drive through the Kenny Hill geological formation before the end of the year. At break-in, a survey confirmed that the TBM was within a reported 20mm on line and level.
- After a period of maintenance, the machine will be relaunch from the in the Sentral Station box end-wall in early 2014 for its next leg to the Pasar Seni Station box. During that time, its partner machine is closing in on breakthrough into the Sentral Station box and is expected to arrive before Chinese New Year in February 2014.
- These two CRTE TBMs are the first machines exported by China Railway Tunnelling Equipment Co. In November, CRTE acquired the intellectual property rights of Wirth TBM and shaft boring machine technology from Aker Wirth and in February 2013 established an international sales office in Hong Kong confirming the company's plan to increase TBM market share outside of China.
Spot-on CRTE EPBM breakthrough
- Meanwhile in Kuala Lumpur, MCC-Gamuda, the JV of Malaysia's two largest civil construction companies inresponsible for construction and delivery of the entire 51km long first line of the Klang Valley Mass Rapid Transit project for the Government's MRT Corporation, is also the contractor in charge of completing the line's underground works through the most difficult kastic limestone geology.
- To complete the 5.8m i.d. twin tube tunnel drives, MCC-Gamuda has procured six VDMs (variable density TBMs) from Herrenknecht. These join two EPBMs from Herrenknecht to work on the section through the Kenny Hill formation and are designed specifically to control excavation of the kastic formations. The machine design combines the principles of EPB and slurry Mixshield concepts and the ability to change quickly from one mode to the other without much adaptation work.
Peter Kenyon, TunnelTalk
- Depending on the requirements, the face is either supported safely by air-compressed supported bentonite slurry or in the earth pressure mode using a screw convey to control extraction of material from the plenum. In addition, the density or viscosity of the bentonite in the slurry mode may also be varied, allowing for flexible reaction to changing conditions in the tunnel face.
Underground section of the 51km long MRT route
Launch sites and drives of each of the 10 project TBMs
- The first of the 6.6m o.d. VDM machines was the first machine on the project to start operation and marked start of tunnelling when it launched from the Cochrane launch shaft in May 2013. It is now progressing through the Pasar Rakyat station zone (the station box not yet excavated to tunnel depth) and is expected to arrive at the interimInai shaft between Pasar Rakyat and Bukit Bintang Central Station, before Chinese New Year in February 2014.
- Passage of the two running tunnels through Pasar Rakyat Station is on a stacked configuration and the second VDM from the Cochrane Station launch box is expected to hole through any day in very early January 2014.
- The third and fourth VDMs are progressing from their Cochrane Station box launch towards the Maluri Station which it will drive through on a parallel running tunnel configuration and on to the transition portal to the surface works on the southern end of the underground section. Both machines are due to reach the Cochrane cut-and-cover crossover box zone in the early days of 2014.
- The first of the last pair of VDMs was launched recently at the intermediate Inai working shaft and will drive the upper of stacked running tunnels towards the Bukit Bintang Station box. The machine has launched in the tight confines of a working shaft using umbilicals, which is a slow and complicated process. Its partner machine is to launch from a parallel working shaft at the Inai site later in 2014.
- To the current underground works Herrenknecht subsidiary companies also delivered 160 segment moulds for the production of a total 100,000 segments; H+E supplied machine conveyor belts; VMT navigations systems are on each Herrenknecht machine; and Techni-Métal supplied multi-service vehicles for delivery of segments into the TBM drives.
- As works on Line 1, the Blue Line, are off to a progressive start, plans for the current Klang Valley MRT master plan envisages construction of three metro lines for an overall network of 150km.
New design TBM tames the Kuala Lumpur karst - TunnelTalk, January 2014
First TBMs launch on Klang Valley MRT - TunnelTalk, June 2013
Chinese TBM maker goes international - TunnelTalk, February 2013
CRTE of China takes over Wirth TBM business - TunnelTalk, November 2013
New-design TBM ready for Malaysia challenge - TunnelTalk, November 2012
MMC-Gamuda orders six TBMs from Herrenknecht - TunnelTalk, April 2012
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