First TBM Being Assembled for SMART Scheme in KLThe Stormwater Management and Road Tunnel (SMART) project is a flood mitigation project being implemented by the government of Malaysia. During exceptionally heavy rain which occurs about once or twice a year, Kuala Lumpur has been experiencing flash floods caused by spillover at the critical confluence of the Klang River and Gombak River. The secondary purpose of this project is to ease traffic congestion at the main artery entering the city centre via the Southern Gateway.The project, costing over RM2 billion, is the first of its kind in the world where the project will incorporate the stormwater tunnel and a road tunnel. A single infrastructure serving two distinct purposes has attracted quite a bit of attention locally and internationally. This unique feature and dual concept incorporating a stormwater and a motorway tunnel is believed to be the first of its kind in the world. The SMART project was incepted by the project proponent, the Malaysian Mining Corp. Engineering Group-Gamuda JV, primarily to mitigate the recurring floods in Kuala Lumpur. However, at the design stage of SMART, the dual purpose concept was born from the ingenuity of the proponents to kill two birds with one stone. Visit www.mmc.com.my and www.gamuda.com.myThe SMART project is implemented under the close supervision of the government, through the Drainage and Irrigation Department and the Malaysia Highway Authority. Engineering support is provided by a local consultant, Sepakat Setia Perunding in association with Mott MacDonald of UK. Visit www.sspsb.com and www.mottmac.comSMART includes a 9.4 km stormwater tunnel, a 3 km double deck motorway tunnel within the stormwater tunnel, ingress and egress connections to the motorway tunnel linking the KL-Seremban highway, ingress and egress connections linking the motorway tunnel to Jalan Sultan Ismail and Jalan Tun Razak, a holding basin at Kampung Berembang (off Jalan Ampang) with diversion and tunnel intake structures, a storage reservoir at Taman Desa, a twin-box culvert to release flood discharge from a storage reservoir to Sungai Kerayong and an operation control centre with administration, supervision, river management and traffic management facilities for management, operation and maintenance of the whole system.Orders were placed in 2003 for two Herrenknecht Mixshield TBMs, 13.21 m in diameter, with slurry face support. The cutterheads of the two Mixshields are of the closed type. They are equipped with material inlet slots. Disc cutters and soft ground tools are arranged equally on the cutterhead to allow both directions of rotation. Each machine is equipped with 48 thrust jacks allowing a maximum thrust force of 93,000 kN. The first TBM for the north drive was shipped to Malaysia where it arrived in early February. Assembly will take place until May followed by testing and commissioning until July. Tunnel boring will commence in July for completion in June 2006. The second machine for the south drive is due to leave Germany this month for arrival in Port Klang in May. Assembly at the site is scheduled between May and August, testing and commissioning right after until October and tunnelling from October 2004 to May 2006. Visit www.herrenknecht.comThe starting point for both Mixshields is the north ventilation shaft. The overburden along the tunnel alignment is generally low, from 10 m to 20 m maximum. The overburden along the rock section is 15 m maximum but generally ranges from 1 to 6 m. One of the machines will bore 5.4 km in northern direction. It will be operated by Wayss & Freytag and BAM NBM. The second will be operated by the MMC-Gamuda JV. This southern section comprises a 4.05 km bored tunnel to be driven in mixed rock and soil sections whereas the northern lot contains parts in complete soft soil conditions. The TBMs will excavate sections in compact and fresh marble and will have to expect sections with karstic developments. Quaternary silty soil and tin mine tailings cover the limestone rock head. The solution process makes the rock head irregular, sometimes dropping to the centrefold of the excavation. The groundwater table is only a few metres below the surface, about 2.6 to 5.2 m on the northern lot and approximately 0.7 to 2.2 m below the surface on the southern lot. The permeability of the soils and rocks will be generally very low but the water inflow will be determined by the karstic cavities or local fractured zones. The tunnel lining consists of prefabricated concrete segments. One ring has a length of 1.7 m and consists of 8 segments plus one key segment. The outside diameter of the tunnel is 12.83 m, the inside diameter is 11.83 m resulting in a segment thickness of 500 mm. The tunnel cross section has a clearance of 110 m2 and contains two intermediate ceilings. The two upper levels will be used for traffic during the dry season, carrying two lanes in each direction. The bottom tunnel cross section will be used for the water conveyance during the rainy season. Read E-News Weekly 9/2004. Click my/16. 14/04. The second Herrenknecht mixshield TBM during factory acceptance in February.